Abraham Zacut’s Signature: A Mystery Solved

Abraham ben Samuel ben Abraham Zacut of Salamanca (1452–1515) is perhaps best known today for his historical work, The Book of Genealogies (ספר יוחסין), but he was also the leading astronomer in the Iberian peninsula at the end of the fifteenth century. His main astronomical work, The Great Composition (החבור הגדול), composed in Hebrew in 1478, consists of canons (a set of instructions) and astronomical tables. A Castilian version of the canons by Juan de Salaya was completed in 1481 with the aid of Zacut. Shortly after the expulsion of Jews from Spain, Zacut arrived in Portugal and was apparently given the title of “royal astronomer” during the reigns of João II (1482–1495) and Manuel I (1495–1521). After Judaism was declared illegal in Portugal in 1497, Zacut went on to North Africa, and subsequently to Jerusalem. His fame among European astronomers (outside the Iberian peninsula) depended on a set of astronomical tables published in Leiria, Portugal, in 1496, with canons in Latin in some copies and Castilian in others, entitled Almanach perpetuum. This was one of the earliest publications of a set of astronomical tables. Although Zacut is mentioned as the author, this does not seem to be true for the canons, which differ in many ways from the Hebrew canons of his Great Composition. According to the colophon, Joseph Vizinus translated Zacut’s text from Hebrew to Latin and then from Latin to Castilian, but this probably does not reflect Vizinus’s precise role in the publication. In any event, it is not clear that Zacut was aware of this edition. All, or some of the tables, in the Almanach perpetuum were later reprinted in Venice in 1498, 1502, 1525, and 1528, and this is an indication of the status of Zacut’s work in the astronomical community at the time. There were also translations (and adaptations) of the printed edition into Arabic.¹

Zacut’s role in Portugal is not easy to reconstruct, and there are many legends of dubious historical value. One fixed point seems to be his signature, “Abraham Zacut, royal astronomer,” on a Portuguese document, dated 9 June 1493.² But this document has long been puzzling, and there is no other signature by Zacut with which to compare it. In 1896 Kayserling published a “facsimile” of the signature which he had received from a Portuguese colleague, Joaquim Mendes dos Remedios.³ In this facsimile two Hebrew letters are crossed out, which seems strange in a signature (see Fig. 1). It turns out that Kayserling (or possibly his Portuguese colleague) was just correcting the Hebrew without indicating that the image had been altered. Indeed, in the facsimile published in 1909 by Lemos no letters are crossed out (see Fig. 2).⁴ But is it likely that Abraham Zacut, a major author of Hebrew texts, would write התוכן מהמלך instead of תוכן המלך (the king’s astronomer)? In any event, the Hebrew expression is a literal translation of a title as it would appear in a Romance language: in modern Portuguese it would be o astrônomo do rei (corresponding to l’astronome du roi in modern French), where Hebrew -מ (or מן) corresponds to the preposition de.⁵ Perhaps the most problematic aspect of this signature is that it was not customary to add the honorific ר' (rabbi) before one’s name in a signature. Moreover, in addition to the given name in a signature, the father’s name and the grandfather’s name were usually included.⁶ Another difficulty concerns the letters at the end of the signature (to be discussed below).

Figure 1.

Kayserling’s “facsimile” of the signature (1896).

Figure 2.

Lemos’s facsimile of the signature (1909).

It seems to me that the simplest solution is to assume that someone acting as Zacut’s agent signed the document for him. In that case, the honorific and the lack of patronymics are plausible, and the awkwardness in the grammar need not be attributed to Zacut himself. The letters at the end of the signature were...