In the years immediately following the publication of Copernicus's De revolutionibus orbium coelestium (Nuremberg, 1543), the illustrious Renaissance astronomer Erasmus Reinhold of Saalfeld (or Rheinholt Salveldensis, 1511-53) issued a commented Greek-and-Latin edition of the first book of Ptolemy's Almagest under the title Ptolemaei Mathematicae constructionis liber primus. It first appeared in Wittenberg, in 1549, from the academic printer Johannes Lufft, and was reprinted in 1569 under the variant title Regulae artis mathematicae. The 'cosmological' book of the Almagest, presenting famous arguments in favour of terrestrial centrality and immobility, appeared thus in a university centre that played a deciding role in the early dissemination of Copernicus. Reinhold himself was one of the astronomers who most significantly contributed to Copernicus's reputation. 1 The printer Guilliaume Cavellat reissued Reinhold's translation of Ptolemy (without the original text) in Paris several times (1556, 1557 and 1560), probably for the students of the Collège de Cambrai. 2 Erasmus Reinhold has been regarded as "the leading mathematical astronomer of the sixteenth century", second only to Copernicus. 3 He was appointed as a professor of mathematics at Wittenberg in the years in which Melanchthon attracted and forged there an entire generation of Lutheran humanists. As a colleague of Nicholas Copernicus's only pupil Georg Joachim Rheticus (1514-74), Reinhold was one of the first readers of De revolutionibus and also contributed to its success thanks to his Prutenicae tabulae (Tübingen, 1551), based on it. These constituted an alternative to the tradition of ephemerides computed from the Alfonsine Tables. 4 Most of the sixteenth-century compilers of new astronomical tables and many ephemerists relied on Reinhold's tables -among them John Field (1520-87) in England, Johannes Stadius (c. 1527-79) in Flanders, Michael Mästlin (1550-1631) and David Origanus (1558-1628) in the German Empire, and Giovanni Antonio Magini (1555-1617) south of the Alps. Thus, Reinhold's tables facilitated a wide dissemination of Copernicus's numerical parameters and, indirectly, of his geometrical models and theories. 5 Still, unlike his colleague, Reinhold kept silent about the heliocentric theory and limited his reception of De revolutionibus to celestial parameters and geometrical modelling. His approach became quite common for mathematicians belonging to the network of Lutheran universities gravitating about Wittenberg and it is currently known as the "Wittenberg interpretation". 6 In the Prutenicae tabulae, Reinhold did not make his 'cosmological' presuppositions explicit, i.e., he did not express his