Alberto Bardi

The history of the science of the stars (astronomy and astrology) in fourteenth-century Byzantium is significantly intertwined with the implications of theological and philosophical controversies. A less-explored astronomical text authored by the fourteenth-century Byzantine scholar Theorodos Meliteniotes (ca. 1320–1393 CE) provides new historical factors toward a historiography of the differences between scientific and theological discourses, their development in the transition to early modern times, and the different historical developments of science in the worlds of the Eastern and Western Churches.

The year 2023 marks the 550th anniversary of the birth of the Polish scholar Nicolaus Copernicus. Usually deemed one of the most emblematic examples of the scientific revolution and the theory of paradigm shift in the history of science, the heliocentric theory proposed by Copernicus in 1543 has fed the minds of philosophers and historians for centuries. Recently, increasing attention has been put on the recognition of the sources that might have influenced Copernicus’s creativity. The outcomes showed that the claims on paradigm shift are pretty shaky, because Copernicus was deliberately in dialogue with Ancient Greek and Arabic authors, and his On the Revolutions of the Celestial Spheres deliberately emulates Ptolemy’s Almagest. In this sense, the essence of the scientific revolution is more an attempt to recreate the debate with ancient authors then a breaking with their paradigms. This study takes a closer examination of Copernicus’s early draft on heliocentrism, the Commentariolus (1510-1515 ca.) and it argues that the birth of the heliocentric theory was first conceived as an attempt to write an Archimedes-like treatise, while the efforts to emulate Ptolemy come at a later stage. On this account, the early Copernicus can be considered an Archimedean.

The debate about the foundations of mathematical sciences traces back to Greek antiquity, with Euclid and the foundations of geometry. Through the flux of history, the debate has appeared in several shapes, places, and cultural contexts. Remarkably, it is a locus where logic, philosophy, and mathematics meet. In mathematical astronomy, Nicolaus Copernicus’s axiomatic approach toward a heliocentric theory of the universe has prompted questions about foundations among historians who have studied Copernican axioms in their terminological and logical aspects but never examined them as a question of mathematical practice. Copernicus provides seven unproved assumptions in the introduction of the brief treatise entitled Nicolaus Copernicus’s draft on the models of celestial motions established by himself, better known as Commentariolus (ca. 1515), published circa 30 years before the final composition of his heliocentric theory (On the revolutions of the heavenly spheres, 1543). The assumptions deal with the renowned Copernican hypothesis of considering the Earth in motion and the Sun, not affected by motion, near the center of the universe. Although Copernicus decides to omit the proofs for the sake of brevity, the deductions in the Commentariolus are supposed to be drawn from the initial seven assumptions. Questions on the nature (are they postulates or axioms?) and the logic (is there an internal rigor?) of those assumptions have yet to be fully explored. By examining Copernicus’s seven assumptions as a question of mathematical practice, it is possible to hold historical, philosophical, and logical aspects of Copernican axiomatics together and understand them as part of Copernicus’s intuition and creativity.

Claudius Ptolemy’s mathematical astronomy originated in Alexandria in Egypt under Roman rule in the second century CE and held for more than a millennium, even beyond the Copernican theories (sixteenth century). To trace the flourishing of such mathematical creativity requires an understanding of Ptolemy’s philosophy of mathematical practice, the ancient commentators of Ptolemaic works, and the historical context of Alexandria in Egypt, a multicultural city which became a cradle of cultures of mathematical practices and blossomed into the Ptolemaic system and its several related outputs between the second and fourth centuries CE. Ptolemy’s mathematical practice will be explored under three lenses: (a) an examination of the mathematical prose of Ptolemy’s Almagest alongside the corresponding passages in its Alexandrian commentaries; (b) the social, material, and semantic layers of Ptolemy’s mathematics; and (c) the conception of true philosophy in Ptolemy’s theory of knowledge. Examining the history and philosophy of Ptolemy’s mathematical practice in Alexandria (1) shows that Ptolemy’s ideals were usually betrayed by the practitioners of his mathematics and (2) proves that its main aspect is constituted by mathematical knowledge arranged in tabular format, that is the so-called astronomical tables, to which Ptolemy’s mathematics owes its successful legacy.

Johannes Müller von Königsberg (1436-1476), better known as Regiomontanus, is widely considered as the most influential astronomer and mathematician of 15th-century Europe. He was active as an astrologer and deemed astrology to be the queen of mathematical sciences. Despite this, Regiomontanus's astrological activity has yet to be fully explored. A brief examination of Regiomontanus's manuscripts shows that his astrological interests were accompanied by interests in the arts and in methods of prognostication. This article studies an unconventional astrological-chiromantical text, whose relevance is threefold: a) it sheds new light on Regiomontanus's astrological interests; b) it enriches our knowledge of Regiomontanus's efforts to learn and understand Greek-Regiomontanus transcribed it into his own manuscript during his sojourn in Italy from 1460-1467; and c) it is the sole extant text in the Greek tradition that provides a system for prognostication from the study of a person's hand, the parts of which are considered as being under the domain of planets. The article provides an English translation of Regiomontanus's transcription, alongside a brief commentary, and studies the intellectual and historical context of that production through manuscript analysis.

Originating in the field of biology, the concept of the hybrid has proved to be influential and effective in historical studies, too. Until now, however, the idea of hybrid knowledge has not been fully explored in the historiography of pre-modern science. This article examines the history of pre-Copernican astronomy and focuses on three case studies—Alexandria in the second century CE; Baghdad in the ninth century; and Constantinople in the fourteenth century—in which hybridization played a crucial role in the development of astronomical knowledge and in philosophical controversies about the status of astronomy and astrology in scholarly and/or institutional settings. By establishing a comparative framework, this analysis of hybrid knowledge highlights different facets of hybridization and shows how processes of hybridization shaped scientific controversies.

The history of astronomy in Byzantium poses great problems of interpretation for Byzantinists and historians of science. This interdisciplinary contribution seeks to understand astronomy in Byzantium from the thirteenth to the fifteenth centuries from the perspective of the Byzantines and to convey it to today's readers. This goal is reached through the study of an astronomical text of that time, the Paradosis or Lessons on the Persian Tables of Astronomy. The present work provides a critical edition of the Paradosis along with a translation and commentary, and discusses the importance of this text in the history of astronomy and the transmission of Islamic astronomy through Byzantium to the West.

This paper is a preliminary study focused on the astronomical manuscript Marcianus latinus VIII.31 (2614) and its socio-historical context of use and production, the Venetian colony of Crete in the 15th century. It is a relevant source for the study of scientific interactions in colonial, multilinguistic, and interreligious contexts in the Eastern Mediterranean for at least two reasons: (a) it contains an unpublished translation into Latin of a popular Byzantine handbook on how to use a set of astronomical tables stemming from Islamic sources, namely the so-called Paradosis of the Persian Tables, a work extensively copied and annotated by very significant Byzantine and Jewish scholars active in Constantinople; and (b) it provides evidence of a Byzantine product being the object of exchange in the interactions between Christians and Jews in the Cretan territory under Venetian rule.

Nel Marc. gr. Z. 333, testimone del testo astronomico intitolato Παράδοσις εἰς τοὺς περσικοὺς κανόνας τῆς ἀστρονομίας, copiato da Bessarione, sono presenti delle aggiunte, dovute all’intervento di Bessarione stesso, che si ritrovano nella tradizione manoscritta dell’opera soltanto nei discendenti del Marc. gr. Z. 333. Tali aggiunte sono tratte da un testo astronomico di Isacco Argiro e da una versione della Paradosis riveduta da Teodoro Meliteniote. L’analisi filologica e paleografica dimostra che in entrambi i casi le aggiunte sono ricavate da un codice di Giovanni Cortasmeno. Ciò dimostra che il Bessarione ebbe Cortasmeno come maestro non solo nella filosofia aristotelica, ma anche nell’astronomia, e che dunque il suo interesse per questa scienza si sviluppò già nella fase poco nota della sua formazione giovanile a Costantinopoli, e non solo, come si riteneva sino ad oggi, sotto la guida di Giorgio Gemisto Pletone a Mistrà dopo il 1431.