Carolingian eclipse rules and the Liber Nemroth: Some remarks on a recent hypothesis
May 2025
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Journal article
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Journal for the History of Astronomy
This short note responds to a recent article on “Occultation Records in the Royal Frankish Annals for A.D. 807: Knowledge Transfer from Arabia to Frankia?” by Ralph Neuhäuser and Dagmar L. Neuhäuser (JHA 55, no. 3). It shows that, contrary to a key claim made in this article, the presence of rules for predicting solar and lunar eclipses in manuscripts associated with the so-called Seven-Book-Computus of 809 is due to the influence of the Liber Nemroth, a text with roots in the pre-Islamic Near East.
Seven-Book-Computus, Carolingian Europe, eclipses, Royal Frankish Annals, Liber Nemroth
From Tunis to Venice: Traces of Maghribī Astronomy and Geography in Manuscripts from Late Medieval Italy
April 2025
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Journal article
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Mediterranea International Journal on the Transfer of Knowledge
4303 Historical Studies, 50 Philosophy and Religious Studies, 43 History, Heritage and Archaeology, 44 Human Society
Were the tables of Ibn Isḥāq al-Tūnisī known in Paris c.1300?
November 2024
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Journal article
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Journal for the History of Astronomy
5101 Astronomical Sciences, 51 Physical Sciences
On some early Latin European measurements of the eccentricity of the solar orbit (1308–1314)
May 2024
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Journal article
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Journal for the History of Astronomy
5101 Astronomical Sciences, 51 Physical Sciences
Geographic longitude in Latin Europe during the twelfth and thirteenth centuries
January 2024
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Journal article
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Archive for History of Exact Sciences
50 Philosophy and Religious Studies, 5002 History and Philosophy Of Specific Fields
Measurements of altitude and geographic latitude in Latin astronomy, 1100–1300
November 2023
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Journal article
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Archive for History of Exact Sciences
50 Philosophy and Religious Studies, 5002 History and Philosophy Of Specific Fields
Astronomical observations in Bologna, Montpellier, and Genoa in the early 14th century: Iohannes de Luna Theutonicus revisited
August 2023
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Journal article
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Journal for the History of Astronomy
5101 Astronomical Sciences, 51 Physical Sciences
A Newly Identified Treatise on the Tables of Marseilles (Twelfth Century) and Its Non-Ptolemaic Planetary Theory
January 2023
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Journal article
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Early Science and Medicine
50 Philosophy and Religious Studies, 5002 History and Philosophy Of Specific Fields
Guillaume des Moustiers' treatise on the armillary instrument (1264) and the practice of astronomical observation in medieval Europe.
October 2021
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Journal article
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Annals of science
This article is devoted to a thirteenth-century Latin text on how to construct, set up, and use a version of the so-called armillary instrument (<i>instrumentum armillarum</i>), which was first described in Ptolemy's <i>Almagest</i> as a tool for measuring ecliptic coordinates. Written in 1264 by Guillaume des Moustiers, bishop of Laon, this hitherto unstudied <i>Tractatus super armillas</i> survives in a single manuscript, where it is accompanied by a copious set of glosses. The text and its glosses jointly offer an unusually detailed account of the instrument's material aspects and methods of assembly. In addition, they reflect a keen awareness of the potential sources of error that may arise in the context of astronomical observation, while making suggestions on how these errors may be minimized or avoided. The <i>Tractatus super armillas</i> accordingly is a valuable source on the observational side of medieval European astronomy, which has often been minimized in modern historical accounts.
Mental Processes, Astronomy, Europe, Text Messaging
A Fourteenth-Century Scholastic Dispute on Astrological Interrogations
January 2021
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Journal article
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Vivarium
50 Philosophy and Religious Studies, 5002 History and Philosophy Of Specific Fields
A medieval value for the circumference of the Earth
July 2020
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Journal article
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Early Science and Medicine
Geographic and astronomical texts from late-medieval Central Europe frequently give 16 German miles, or miliaria teutonica, as the length of a degree of terrestrial latitude. The earliest identifiable author to endorse this equivalence is the Swabian astronomer Heinrich Selder, who wrote about the length of a degree and the circumference of the Earth on several occasions during the 1360s and 1370s. Of particular interest is his claim that he and certain unnamed experimentatores established their preferred value empirically. Based on an analysis of relevant statements in Selder’s extant works and other late-medieval sources, it is argued that this claim is plausible and that the convention 1° = 16 German miles was indeed the result of an independent measurement.
circumference of the Earth, medieval metrology, medieval geodesy, medieval astronomy, Heinrich Sedler
‘With utmost certainty’: two late medieval pioneers of technical chronology
March 2020
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Journal article
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Journal of Medieval History
This article focuses on the chronological methods developed and deployed by two little known medieval scholars, Giles of Lessines (active in the 1260s) and Heinrich Selder (1370s), both of whom made noteworthy advances in the use of astronomy to establish dates and intervals between events in ancient history. Based on their reading of Ptolemy's Almagest, both authors emphasised the importance of dated astronomical observations, such as eclipses, arguing that the recorded intervals between these observations were endowed with a unique degree of reliability. Several key examples of how they mobilised Ptolemy's astronomical data to rectify parts of the timeline between the creation of the world and the present will be discussed. These show that the technical arguments contained in Giles’ and Selder's writings reached a level of sophistication and accuracy that has previously only been associated with chronologers of the early modern and later periods.
chronology, Roger Bacon, Giles of Lessines, Heinrich Selder, astronomy
An Alfonsine universe: Nicolò Conti and Georg Peurbach on the threefold motion of the fixed stars
February 2020
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Journal article
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Centaurus
Among the characteristic features of Georg Peurbach's influential Theoricae novae planetarum (1454) was a model of the motion of the fixed stars, based on the Alfonsine Tables, that involved both an eighth sphere undergoing trepidation and a ninth sphere subject to linear precession. Instead of being an innovation on Peurbach's part, the model in question can be shown to have been derived from an obscure treatise De triplici motu octave spere written in 1450 by the Paduan astrologer Nicolò Conti (d. 1468). The main purpose of this article is to highlight relevant parallels between the two works, especially in their use of diagrams, and to present evidence of personal ties between Conti and Peurbach, which explain how the model in question was transmitted from Padua to Vienna. In addition, it discusses the astrological impetus behind Conti's physical model, which was based on the notion that the slow motion of the fixed stars influences the course of history.
Medieval Europe’s satanic ciphers: on the genesis of a modern myth
February 2020
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Journal article
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British Journal for the History of Mathematics
The purpose of this article is to investigate the genesis and growth of a historical canard that can be encountered in numerous popular as well as some scholarly publications devoted to the history of mathematics. According to one of the core elements of this story, the number or symbol for zero was the cause of much anxiety in medieval Europe, as its unusual properties caused it to be associated with the Devil or with black magic. This anxiety is supposed to have extended to the entire system of Hindu-Arabic numerals, such that the use of these numerals was banned by the Church or by other powerful institutions. I shall argue that this narrative is false or unsubstantiated at nearly every level of analysis. Some elements arose from an unwarranted interpretation of medieval sources, while others are based on the unbridled imagination of certain modern authors.
The Liber theoreumacie (1214) and the early history of the quadrans vetus
February 2020
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Journal article
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Journal for the History of Astronomy
The Liber theoreumacie is a neglected work of practical geometry, written in Strasbourg in 1214, which sheds valuable light on the study and practice of astronomy in early thirteenth-century Europe. In this article, I focus on the first two chapters of Book IV, which both deal with the construction of horary instruments. The first of these chapters contains the earliest known account of the type of universal horary quadrant known as quadrans vetus, which is here given a biblical pedigree by labelling it the “sundial of Ahaz.” The second chapter describes a graphical method of inscribing hour markings on the surface of an astrolabe’s alidade, which appears to have been introduced into Latin Europe by the twelfth-century translator John of Seville. A critical edition and translation of the relevant passages will conclude the article.
quadrant, astrolabe, John of Seville, precession, thirteenth-century astronomy, astronomical instruments
An overlooked construction manual for the Quadrans Vetustissimus
December 2019
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Journal article
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Nuncius
This article presents an edition and brief analysis of the previously overlooked text De compositione quadrae, which is transmitted as part of a scientific miscellany assembled at Worcester Cathedral Priory no later than 1140. De compositione quadrae offers hitherto unavailable information on the construction of the so-called quadrans vetustissimus, a version of the universal horary quadrant circulating in Latin Europe during the eleventh and twelfth centuries. It is particularly noteworthy for its description of a graphical method of inscribing the months of the Julian calendar on the quadrant’s cursor, which successfully approximates the sine function that determines the change of solar declination in the course of a year.
Book Review: Medieval Astrology Practically Applied
May 2019
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Journal article
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Journal for the History of Astronomy
5101 Astronomical Sciences, 51 Physical Sciences
Pierre d’Ailly’s Tractatus de vero cyclo lunari: Introduction and Edition
May 2019
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Journal article
Glorious science or “dead dog”? Jean de Jandun and the quarrel over astrology in fourteenth-century Paris
April 2019
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Journal article
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Vivarium
This article edits and examines a little-known epistolary treatise datable to 1322, which survives in a fifteenth-century manuscript in the Herzog-August-Bibliothek, Wolfenbüttel. The author of this work was engaged in a heated argument with the Parisian philosopher Jean de Jandun over the status and rationality of astrology. Jean’s pro-astrological stance is documented in a letter dated 28 October 1321, which survives for having been appended to the main treatise. In responding to Jean de Jandun’s letter, the author delivered a trenchant critique of astrology grounded almost entirely in philosophical, as opposed to theological, ideas, addressing issues such as empirical evidence, causality, and contingency. The author’s way of pointing out ruptures between astrology and Aristotelian natural philosophy marks him out as an intellectual precursor to the much better-known anti-astrological polemics written later in the same century by Parisian thinkers such as Nicole Oresme and Heinrich von Langenstein.
Jean de Jandun, Geoffroy de Meaux, astrology, University of Paris
Robert Grosseteste’s Compotus
March 2019
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Scholarly edition
Astronomical and Cosmological Dubia in the Cistercian Pierre Ceffons’ In II Sententiarum, distinctio 1
January 2019
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Journal article
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Cahiers de l’Institut du Moyen-Âge Grec et Latin
Jean des Murs’s Canones tabularum Alfonsii of 1339
January 2019
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Journal article
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Erudition and the Republic of Letters
Among the works by Jean des Murs that have yet to be printed are his Canones tabularum Alfonsii, which he wrote in 1339 during his last attested stay at the Collège de Sorbonne. One element of particular interest in this concisely worded text is Jean’s discussion of the length of the solar year, which was the first to take into consideration the consequences of the Alfonsine precession model for the length of the tropical year. Another is his approach to finding the time of true syzygy, which can be compared with some of his earlier writings on the same topic. Taken together, these writings reveal something about Jean’s development as an astronomer over time, as he adjusted his preferred method of syzygy computation in reaction to empirical data. The article concludes with a look at the chapters devoted to the calculation of eclipse times and magnitudes, which turn out to be strongly influenced by John of Genoa’s Canones eclipsium, written in 1332.
Jean des Murs, eclipses, University of Paris, astronomical tables, John of Genoa, Collège de Sorbonne, medieval astronomy, Alfonsine Tables
Henry Bate’s 'Tabule Machlinenses': The earliest astronomical tables by a Latin author
November 2018
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Journal article
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Annals of Science
The known works of the medieval astronomer/astrologer Henry Bate (1246–after 1310) include a set of planetary mean motion tables for the meridian of his Flemish hometown Mechelen. These tables survive in three manuscripts representing two significantly different recensions, but have never been examined for their principles of construction or underlying parameters. Such analysis reveals that Bate employed an unusual value for the length of the tropical year (c.365 1/4 − 1/112 days), which was probably derived by comparing ancient and contemporary observations of the vernal equinox. In addition, there are clear signs that Bate kept revising his parameters for the mean motions of Venus and the three superior planets, none of which can be traced back to earlier sources. Together with some of Bate’s preserved statements, these findings support the conclusion that the Tabule Machlinenses were unique among the astronomical tables produced in medieval Latin Christendom for using independently derived parameters that were the result of new observations. Bate’s achievement connects him to a wider milieu of astronomers operating in late-thirteenth-century Paris, who put an increased emphasis on observation and the critical examination of received data.
William of Saint-Cloud, astronomical tables, Ptolemy, Henry Bate, medieval astronomy, Paris, Abraham Ibn Ezra, astronomical observations
Ptolemaic orbs in twelfth-century England: A study and edition of the anonymous 'Liber de motibus planetarum'
March 2018
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Journal article
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Mediterranea: International Journal on the Transfer of Knowledge
This article offers the first study and critical edition of the Liber de motibus planetarum (Lmp), a neglected Latin text on planetary theory that appears anonymously and without any clear indication of date or place of origin in nine manuscripts of the thirteenth to fifteenth centuries. An analysis of its sources and parallels to other Latin treatises and translations from Arabic indicates that the Lmp originated in England in the third quarter of the twelfth century. A plausible terminus post quem is provided by the appearance of similar passages in the anonymous treatise Ptolomeus et multi sapientum (1145), which can be linked to Abraham Ibn Ezra and his astronomical tables for the meridian of Pisa. The Lmp would appear to be historically significant for its relatively detailed textual and diagrammatic presentations of Ptolemy’s planetary models as composed of multipart physical orbs. While it is generally accepted that physicalized or ‘orbed’ versions of these models entered Latin astronomy through the influence of Ibn al-Haytham’s Maqāla fī hayʾat al-ʿālam (On the Configuration of the World), the early history of this idea in a Latin context has not been studied to any deeper extent. In this regard, the Lmp offers clear evidence that Ptolemaic orbs and diagrams representing them already were a part of Latin astronomy three centuries before Peuerbach’s Theoricae novae planetarum (1454).
Abraham Ibn Ezra, Ptolemy, Islamic astronomy, Latin astronomy, Ibn al-Haytham, Latin translations
Scandalous Error
March 2018
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Book
<p>The Gregorian calendar reform of 1582, which provides the basis for the present-day Western civil calendar, has often been portrayed as a triumph of early modern scientific culture and an expression of papal ambition in the wake of the Counter-Reformation. Much less attention has been paid to our calendar’s intellectual and material roots in the European Middle Ages, when the reckoning of time by means of calendrical cycles was a topic of central importance to education and learned culture. For centuries prior to the Gregorian reform, astronomers, mathematicians, theologians, and even Church councils had been debating the necessity of improving or emending the existing ecclesiastical calendar, which throughout the Middle Ages kept growing out of sync with the astronomical phenomena at an alarming pace. Scandalous Error uses a broad base of sources, many of them unpublished or previously unknown, to paint the first full-scale survey of the medieval debate surrounding the calendar and its astronomical underpinnings.</p>
John Holbroke, the Tables of Cambridge, and the “true length of the year”: A forgotten episode in fifteenth-century astronomy
January 2018
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Journal article
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Archive for History of Exact Sciences
This article examines an unstudied set of astronomical tables for the meridian of Cambridge, also known as the Opus secundum, which the English theologian and astronomer John Holbroke, Master of Peterhouse, composed in 1433. These tables stand out from other late medieval adaptations of the Alfonsine Tables in using a different set of parameters for planetary mean motions, which Holbroke can be shown to have derived from a tropical year of 36514 – 1132 or 365.(24) ̅ days. Implicit in this year length was a 33-year cycle of repeating solar longitudes and equinox times, which has left traces in other astronomical tables from fifteenth-century England. An analysis of the manuscript evidence leads to the conclusion that Holbroke owed his value for the “true length of the year” to a certain Richard Monke, capellanus de Anglia, who employed this parameter and the corresponding 33-year cycle in an attempt to construct a perfect and perpetual solar calendar, leading to his Kalendarium verum anni mundi of 1434.
Zaccaria Lilio and the shape of the earth: A brief response to Allegro’s “Flat earth science”
July 2017
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Journal article
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History of Science
This is a response to James J. Allegro’s article “The bottom of the universe: Flat earth science in the Age of Encounter,” published in Volume 55, Number 1, of this journal. Against the solid consensus of modern scholars, Allegro contends that the decades around 1500 saw a resurgence of popular and learned doubts about the existence of a southern hemisphere and the concept of a spherical earth more generally. It can be shown that a substantial part of Allegro’s argument rests on an erroneous reading of his main textual witness, Zaccaria Lilio’s <i>Contra Antipodes</i> (1496), and on a failure adequately to place this source in the context of the cosmographical debate of the late-fifteenth and early-sixteenth centuries. Once this context is taken into account, the notion that Lilio was a flat-earther falls flat.
flat earth
, Age of Discovery
, Zaccaria Lilio, cosmography
, Columbus
, 1492
, Antipodes
From the true Birth Year of Christ
June 2017
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Journal article
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ISIS
Strategic Skepticism: A Reappraisal of Nicholas of Cusa’s Calendar Reform Treatise
June 2017
|
Chapter
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Le temps des astronomes: l’astronomie et le décompte du temps de Pierre d’Ailly à Newton
Walcher of Malvern: De lunationibus and De Dracone
April 2017
|
Book
A reluctant innovator: Greco-Arabic astronomy in the Computus of Magister Cunestabulus (1175)
March 2017
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Journal article
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Early Science and Medicine
This article is dedicated to the obscure Computus of Magister Cunestabulus (England, 1175), which offers a unique spotlight on the way the twelfth-century ‘Renaissance’ in mathematical astronomy impacted the Latin computistical tradition. Armed with an unusually broad array of sources newly translated from Arabic, among them Ptolemy’s Almagest, Cunestabulus applied his advanced knowledge in the service of traditional Latin learning and established Church doctrine, defending the non-existence of Antipodeans in the southern hemisphere as well as the astronomical foundations of the ecclesiastical computus. His intricate explanation of the error underlying the Julian calendar, which was based on the Arabic theory of the ‘access and recess of the eighth sphere’, makes for a technically sophisticated and conceptually intriguing case of Graeco-Arabic science being used for apologetic ends in twelfth-century Latin writing.
Chronologically confused: Claudius of Turin and the date of Christ’s passion
January 2017
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Chapter
|
Late Antique Calendrical Thought and its Reception in the Early Middle Ages
Astronomy and calendar reform at the Curia of Pope Clement VI: a new source
December 2016
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Journal article
|
Annals of Science: a review of the history of science since the thirteenth century
The article introduces a previously unknown fourteenth-century treatise on computus and calendrical astronomy entitled Expositio kalendarii novi, whose author proposed elaborate solutions to the technical flaws inherent in the calendar used by the Roman Church. An analysis of verbal parallels to other contemporary works on the same topic makes it possible to establish that the Expositio was produced in the context of a calendar reform initiative led by Pope Clement VI in 1344/45 and that this anonymous text is probably identical to a ‘great and laborious work’ on the calendar that the monk Johannes de Termis prepared for the pope around this time. Its author strove to make an original contribution by extracting new astronomical parameters from both ancient and contemporary data, which made him arrive at an estimate of the length of the tropical year that was independent of the then-current Alfonsine Tables. With its suggestion to remove eleven days from the Julian calendar and to correct the calendar through modified leap-year rhythms and periodically adjusted sequences of lunar epacts, the proposal enshrined in the Expositio exhibits some remarkable similarities to the Gregorian reform of the calendar promulgated in 1582. Although its influence on the latter must remain a matter of speculation, the newly discovered text sheds a revealing light on the history of medieval calendar reform debates and on the mathematical sciences practiced at the Avignon court of Clement VI.
Criticism of trepidation models and advocacy of uniform precession in medieval Latin astronomy
November 2016
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Journal article
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Archive for History of Exact Sciences
A characteristic hallmark of medieval astronomy is the replacement of Ptolemy’s linear precession with so-called models of trepidation, which were deemed necessary to account for divergences between parameters and data transmitted by Ptolemy and those found by later astronomers. Trepidation is commonly thought to have dominated European astronomy from the twelfth century to the Copernican Revolution, meeting its demise only in the last quarter of the sixteenth century thanks to the observational work of Tycho Brahe. The present article seeks to challenge this picture by surveying the extent to which Latin astronomers of the late Middle Ages expressed criticisms of trepidation models or rejected their validity in favour of linear precession. It argues that a readiness to abandon trepidation was more widespread prior to Brahe than hitherto realized and that it frequently came as the result of empirical considerations. This critical attitude towards trepidation reached an early culmination point with the work of Agostino Ricci (1513), who demonstrated the theory’s redundancy with a penetrating analysis of the role of observational error in Ptolemy’s Almagest.
Josephus and New Testament Chronology in the Work of Joseph Scaliger
October 2016
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Journal article
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International Journal of the Classical Tradition
Bede and the Future
June 2016
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Journal article
|
ENGLISH HISTORICAL REVIEW
Vanitas vanitatum et super omnia vanitas: The astronomer Heinrich Selder and a newly discovered fourteenth-century critique of astrology
April 2016
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Journal article
|
Erudition and the Republic of Letters
A previously unknown treatise on historical chronology (Tractatus de tempore dominice annunciationis, nativitatis et passionis), written by a southern German author between 1371 and 1378, preserves an unusually sophisticated and penetrating scholarly critique of astrology. The main purpose of this article is to introduce and analyze this important work, which is characterized by its close attention to technical astronomical detail and the use of empirical data to refute astrological doctrines. Comparison will be made to the contemporary anti-astrological works of Nicole Oresme and Heinrich of Langenstein, from which the newly discovered Tractatus differs in a number of significant aspects, underscoring its originality. It will be argued that this anonymously transmitted work was authored by the obscure Swabian astronomer Heinrich Selder, whose Canones tabularum Alphonsinarum (1365) are noteworthy for their critical remarks on the Alfonsine Tables.
Thomas Strzempiński, Hermann Zoest, and the Initial Stages of the Calendar Reform Project Attempted at the Council of Basel (1434–1437)
February 2016
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Journal article
|
Cahiers de l’Institut du Moyen-Âge Grec et Latin
Controversial Rimes: Calender Reforms in the Old Empire 1582-1700
January 2016
|
Journal article
|
GERMAN QUARTERLY
Duking it Out in the Arena of Time: Chronology and the Christian–Jewish Encounter (1100–1600)
January 2016
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Journal article
|
Medieval Encounters
5005 Theology, 4303 Historical Studies, 50 Philosophy and Religious Studies, 43 History, Heritage and Archaeology
Magister Rheticus and his School Mates: The Struggle for Knowledge and Implementation of the heliocentric World System of Copernicus around 1540/50
January 2016
|
Journal article
|
GERMAN QUARTERLY
The Early History of Man and the Uses of Diodorus in Renaissance Scholarship: From Annius of Viterbo to Johannes Boemus
January 2016
|
Chapter
|
For the Sake of Learning
47 Language, Communication and Culture, 4705 Literary Studies
Walter Odington's De etate mundi and the Pursuit of a Scientific Chronology in Medieval England.
January 2016
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Journal article
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Journal of the history of ideas
This article deals with a forgotten treatise on the age of the world, written between 1308 and 1316 by Walter Odington, a monk of Evesham Abbey, otherwise known for his writings on alchemy and music theory. By tracing the sources and rationale behind Odington's arguments and comparing them with those of other medieval authors, the article attempts to shed new light on the state of chronological scholarship in England in the eleventh to fourteenth centuries, when astronomical and astrological methods were freely used to supplement or replace scriptural interpretation, yielding creative and unexpected results.
Bede’s horologium: Observational Astronomy and the Problem of the Equinoxes in Early Medieval Europe (c.700–1100)*
October 2015
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Journal article
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The English Historical Review
4301 Archaeology, 4303 Historical Studies, 43 History, Heritage and Archaeology
Medieval Astronomy in Catalonia and the South of France: The ‘Improved’ Lunar Kalendarium of Friar Raymond (Ramon) Bancal (ca. 1311) and Its Predecessors
June 2015
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Journal article
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LLULL : boletin de la Sociedad Espanola de Historia de las Ciencias
Science at the Papal Palace: Clement VI and the Calendar Reform Project of 1344/45
May 2015
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Journal article
|
Viator
43 History, Heritage and Archaeology, 47 Language, Communication and Culture, 4303 Historical Studies, 4705 Literary Studies
The Astronomical Data in the Très Riches Heures and their Fourteenth-Century Source
May 2015
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Journal article
|
Journal for the History of Astronomy
5101 Astronomical Sciences, 51 Physical Sciences
Alfred Lohr, Der Computus Gerlandi. Edition, Übersetzung und Erläuterungen. (Sudhoffs Archiv, Beihefte, H. 61.) Stuttgart, Steiner 2013
April 2015
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Journal article
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Historische Zeitschrift
4303 Historical Studies, 43 History, Heritage and Archaeology
Critical Analysis of The Alfonsine Tables in the Fourteenth Century: The Parisian Expositio Tabularum Alfonsii of 1347
February 2015
|
Journal article
|
Journal for the History of Astronomy
5101 Astronomical Sciences, 51 Physical Sciences
Johannes Keck, the Council of Basel and the forgotten Easter controversy of the year 1444
January 2015
|
Journal article
|
Deutsches Archiv fur Erforschung des Mittelalters
John of Murs and the Treatise Autores kalendarii (1317): A Problem of Authorship.
January 2015
|
Journal article
|
Sudhoffs Archiv
José Chabás & Bernard R. Goldstein, A survey of European astronomical tables in the late middle ages and José Chabás & Bernard R. Goldstein, Essays on medieval computational astronomy
January 2015
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Journal article
|
Peritia
4303 Historical Studies, 43 History, Heritage and Archaeology
Roman vs. Arabic Computistics in Twelfth-Century England: A Newly Discovered Source (Collatio Compoti Romani et Arabici).
January 2015
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Journal article
|
Early science and medicine
A frequently overlooked aspect of the knowledge transfer from Arabic into Latin in the twelfth century is the introduction of the Islamo-Arabic calendar, which confronted Western computists with a radically different scheme of lunar reckoning that was in some ways superior to the 19-year lunar cycle of the Roman Church. One of the earliest sources to properly discuss this new system and compare it to the old one is the anonymous Collatio Compoti Romani et Arabici, found in a manuscript from Tewkesbury Abbey, Gloucestershire. This article contains the first edition and translation of this previously unknown text, preceded by an analysis of its content and sources. As will be argued, the text was written in the second quarter of the twelfth century as a reaction to the astronomical tables of al-Khwāizmī, recently translated by Adelard of Bath, as well as to eclipse observations that had exposed the flaws of the 'Roman' computation.
Astronomy, Time, Arab World, Roman World, History, Medieval, England, Astronomical Phenomena
John of Pulchro Rivo and John of Saxony: A Mise au Point
May 2014
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Journal article
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Journal for the History of Astronomy
5101 Astronomical Sciences, 51 Physical Sciences
A tool for many purposes: Hermann Zoest and the medieval Christian appropriation of the Jewish calendar
April 2014
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Journal article
|
Journal of Jewish Studies
5005 Theology, 4303 Historical Studies, 50 Philosophy and Religious Studies, 43 History, Heritage and Archaeology
Calendars Beyond Borders: Exchange of Calendrical Knowledge Between Jews and Christians in Medieval Europe (12th-15th Century)
March 2014
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Journal article
|
Medieval Encounters
43 History, Heritage and Archaeology, 4303 Historical Studies, 50 Philosophy and Religious Studies, 5004 Religious Studies, 5005 Theology
The Reception and Application of Arabic Science in Twelfth-Century Computistics: New Evidence from Bavaria
February 2014
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Journal article
|
Journal for the History of Astronomy
5101 Astronomical Sciences, 51 Physical Sciences
Climate, Astrology and the Age of the World in Thirteenth-Century Thought; Giles of Lessines and Roger Bacon on the Precession of the Solar Apogee
January 2014
|
Journal article
|
Journal of the Warburg and Courtauld Institutes
4303 Historical Studies, 50 Philosophy and Religious Studies, 43 History, Heritage and Archaeology, 5002 History and Philosophy Of Specific Fields
Me pudet audire Iudeum talia scire: A late medieval Latin school text on the Jewish calendar
January 2014
|
Journal article
|
Time, Astronomy, and Calendars
Medieval Latin Christian texts on the Jewish calendar a study with five editions and translations
January 2014
|
Journal article
|
Time, Astronomy, and Calendars
Origen, Climate Change, and the Erosion of Mountains in Giles of Lessines’s Discussion of the Eternity of the World ( c . 1260)
January 2014
|
Journal article
|
The Mediaeval Journal
43 History, Heritage and Archaeology, 47 Language, Communication and Culture, 4303 Historical Studies, 4705 Literary Studies
A Sixteenth-Century Debate on the Jewish Calendar: Jacob Christmann and Joseph Justus Scaliger
December 2013
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Journal article
|
Jewish Quarterly Review
5005 Theology, 50 Philosophy and Religious Studies, 5002 History and Philosophy Of Specific Fields
An Eleventh-Century Chronologer at Work: Marianus Scottus and the Quest for the Missing Twenty-Two Years
April 2013
|
Journal article
|
Speculum
43 History, Heritage and Archaeology, 4303 Historical Studies, 35 Commerce, Management, Tourism and Services, Generic health relevance
Early Christian chronology and the origins of the Christmas date: In defense of the "calculation theory"
The Meaning of Judaeus and the Myth of Jewish Male Menses in a Late Medieval Astronomical School Text*
January 2013
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Journal article
|
European Journal of Jewish Studies
5005 Theology, 4303 Historical Studies, 50 Philosophy and Religious Studies, 43 History, Heritage and Archaeology
The Origins of the Christmas Date: Some Recent Trends in Historical Research
December 2012
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Journal article
|
Church History
5004 Religious Studies, 4303 Historical Studies, 50 Philosophy and Religious Studies, 43 History, Heritage and Archaeology
Nicholas Trevet and the Chronology of the Crucifixion
July 2012
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Journal article
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The Mediaeval Journal
43 History, Heritage and Archaeology, 47 Language, Communication and Culture, 4303 Historical Studies, 4705 Literary Studies
Augustine and the Shape of the Earth
December 2011
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Journal article
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Augustinian Studies
50 Philosophy and Religious Studies, 43 History, Heritage and Archaeology
From Sukkot to Saturnalia: The Attack on Christmas in Sixteenth-Century Chronological Scholarship
October 2011
|
Journal article
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Journal of the History of Ideas
4303 Historical Studies, 50 Philosophy and Religious Studies, 43 History, Heritage and Archaeology, 5002 History and Philosophy Of Specific Fields
Noah's Calendar: The Chronology of the Flood Narrative and the History of Astronomy in Sixteenth- and Seventeenth-Century Scholarship
January 2011
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Journal article
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Journal of the Warburg and Courtauld Institutes
4705 Literary Studies, 43 History, Heritage and Archaeology, 47 Language, Communication and Culture, 4303 Historical Studies, 50 Philosophy and Religious Studies, 5002 History and Philosophy Of Specific Fields
Alden A. Mosshammer, The Easter Computus and the Origins of the Christian Era
September 2009
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Journal article
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Byzantinische Zeitschrift
4303 Historical Studies, 43 History, Heritage and Archaeology
