in the astronomical techniques needed to practice as an astrologer, as well as in the principles of astrology itself. While he only occasionally alludes to astrological concepts in his writing, we may presume that he was known for this proficiency in at least some court circles. In this connection, one of his students records Duran’s astrologically informed clarification of an obscure comment by Abraham ibn Ezra (1089–1164) on the Bible. According to Duran’s explanation, biblical sacrifices—which presumably mitigated the consequences of negative astrological configurations—were instituted on the new moon, the first day of the month, because it is at the time of the conjunction of the moon and the sun that “the judgments of the lower world are decreed.” Similarly, sacrifices were offered on the seventh day of the month because on that day the aspect of the moon relative to the sun is negative. In addition, Passover and Sukkot—and the sacrifices associated with those holidays—were set to begin on the fifteenth day of the month, when the sun and moon are in opposition, again a negative configuration.54 Similar material appears in Duran’s letter on the number seven (“On the Hebdomad”).
In 1395, Duran completed his first independent treatise, Ḥeshev ha-Efod, a manual on the Jewish calendar. As I discuss in Chapter 7, this text, composed a mere three or so years following his conversion, shows his unabated interest in Jewish issues. The twenty-third chapter, composed in verse form, contains a unique reference to Duran’s Hebrew name, Isaac ben Moses ha-Levi:
And this will be an ordinance for thee for generations until the High Priest stands at the mystery of the Urim and Tummim.
It was composed by Isaac son of Moses, a Levite; his Rock is not like [their] images.55
It is a gift for Moses, great in works, of the house of Hasdai, Levites of the pure ones56
Who will grow and flourish like the palm tree, in his day may the Rock gather the scattered ones,
And the rest of my acquaintances and friends and noble ones and those who listen to me, [the] companions,
May God bring them together to Mount Zion in song and verse, on the wings of eagles.57
These lines, full of longing for the messianic age, invoke an image of the high priest restored to his place in the Temple, arrayed in his sacred garments and “standing at the mystery” of the Urim and Tummim. Duran may be relying here on the exegetical tradition that construed the biblical Urim and Tummim as some sort of astronomical instrument, perhaps an astrolabe, by which the future could be foretold, hence of particular relevance in a treatise devoted to the computation of the calendar.58 And the Urim and Tummim were likewise closely associated with the efod, another of the priestly garments regarded as useful in astrological divination.59
At the very end of this work, Duran again makes reference to the Urim and Tummim, in a similar context:
And with this, what was intended [in this book] has been completed. It will suffice for the whole time that this exile continues, until the [high] priest stands at the Urim and Tummim, and also [it will be useful] in those days, [because] in that time I think that the fixed [times] for the festivals of the Lord will continue, according to the secret of the above-mentioned intercalation, for its foundation is in the mountains of true investigation, and its reasons were explained, [reasons] that stand as [long as] the days of the sun upon the earth, and they indicate its perpetuity, like the perpetuity of the Torah, and all the more so, according to the opinion of the one who says that it is an inheritance for us from Moses our Teacher, peace be upon him.60
Here Duran evidently associates the Urim and Tummim specifically with the restoration of the Temple service. Strongly evocative of his rationalist suppositions is the suggestion that because the Jewish calendrical rules are based on “true investigation” (presumably, astronomy), which is as enduringly true as the Torah itself, they will remain valid into the messianic age.
Finally, Duran includes in his introduction to Ḥeshev ha-Efod a direct reference to his pseudonym and its relation to the year of the riots: “And as for me, from the day when the Lord poured out his anger like water upon the exile of Jerusalem which is in Sefarad, this is my name forever, in the efod is its surrogate [temurah]. Therefore have I called it Ḥeshev ha-Efod.”61 In its biblical context (Lev. 27:10), temurah, “surrogate” or “substitute,” refers specifically to the exchange of one sacrificial animal for another. Duran is signaling that his personal Hebrew acronym, Efod, is also a token of his new identity, not only a way of atoning or offering up a sacrifice for an apparent desertion of the faith but an actual surrogate for the Honoratus de Bonafide he has become in the eyes of society. It is as the Efod that Duran writes his postconversion works; he titles them according to his new identity, The Cincture of the Efod (Ḥeshev ha-Efod) and The Work of the Efod (Ma‘aseh Efod).
In the poem quoted above, Duran dedicates Ḥeshev ha-Efod to an individual named Moses of the house of Hasdai, a Levi.62 It is possible though by no means certain that the Hasdai here refers to Hasdai Crescas. Duran does mention students of his, also “of the sons of Hasdai,” who are again labeled Levites in his introduction to Ma‘aseh Efod (1403), but these are equally difficult to identify.63
Dedicatees are not necessarily friends, or even acquaintances, but there are in fact a number of individuals whom we can associate with Duran. These are his correspondents, whom we know from the epistles addressed to them. Since they sometimes refer to each other in their letters, they constitute a kind of “circle.”
For example, Duran wrote a letter concerning an astronomical question to a Shealtiel Gracian.64 In that letter, Duran refers to an En Meir Crescas, apparently known to both of them, who had in his hands a discussion of the quadrant about which Shealtiel Gracian had inquired. Another, unnamed student, in a manuscript recording astronomical notes, many of which derive from Duran, includes an excerpt from the technical section of Duran’s letter to Shealtiel. Solomon Bonafed (1370/1380–c. 1445) of Zaragoza, a poet and avid correspondent, circa 1413 addresses a poem to Profayt Duran, and mentions him in a letter to their apparently mutual friend Shealtiel Gracian.65 In 1393, Duran composed his eulogy for Rabbi Abraham ben Isaac ha-Levi of Girona and sent it to the rabbi’s son, Joseph; Meir Crescas transcribed a copy of this eulogy into a manuscript of his own. David Bonet Bonjorn, the son of the famous Perpignan astronomer, was the “addressee” of Al tehi ka-avotekha, and the astronomically inclined student mentioned above seems to have been working with a manuscript that had been copied by David Bonjorn’s father, Bonet David Bonjorn (Jacob ben David Po‘el, Perpignan, fl. 1361), as we will see in the following chapter.
Duran seems also to have been acquainted with the two sons of Benveniste ben Lavi (d. 1411). Introducing Duran’s explication of one of Abraham ibn Ezra’s riddle poems, Meir Crescas mentions the request his master received from “two golden cherubs, youngsters, from among the great ones of the land, and from its noble ones, the great sons of Benveniste.”66 One of these sons was the poet Vidal de la Cavalleria (otherwise known as Joseph ben Benveniste ben Lavi, or Vidal Abenlavi, d. between 1445 and 1456), also of Saragossa. He, too, was a friend of Solomon Bonafed,67 and is known to have converted to Christianity at some point before May 22, 1414. About Joseph ben Lavi’s brother, little is known beyond his name: “Juan de la Cavalleria, also called Bonafos.”68
Four acquaintances of Duran bore the name of Joseph. First is Joseph ben Lavi (Benveniste). There is, second, a student “Joseph,” who composed an introductory poem to his copy of Duran’s Ḥeshev ha-Efod,69 but we have no way of identifying him. Then there is Joseph, son of Abraham ben Isaac ha-Levi of Girona. And fourth is the Joseph Zarch/Zarqo found in Italy using Duran’s name as a passport to the good graces of Yeḥiel
