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On Rashi, Maimonides and a lost Talmudic commentator - Joseph ben Yahaboy: T-S Ar. 49.163

by Amir Ashur


This fragment of a commentary to BT Giṭṭin is written in Hebrew but cites other commentators in their original Judaeo-Arabic. It caught my attention particularly due to the fact that it cites Maimonides’ Mishna commentary. Maimonides is mentioned here probably during his lifetime, for his name lacks the blessing for the dead, which is appended here after the names of other commentators. When I read the fragment, I saw that Rashi was mentioned side by side with Maimonides. To the best of my knowledge, it is the only Talmudic commentary from Maimonides’ lifetime that cites these two commentators together.


T-S Ar.49.163 recto

T-S Ar.49.163 recto


Maimonides’ familiarity with Rashi’s Talmudic commentary has been a point of discussion by scholars. While most scholars have believed that "Maimonides apparently did not know any of Rashi's Commentaries,"[1] it has recently been suggested that Maimonides was in fact familiar with them.[2] Some of Rashi’s commentaries are listed in book lists from the Genizah written by Joseph ben Jacob Rosh ha-Seder – a contemporary of Maimonides and his son Abraham,[3] and we have copies of Rashi’s commentaries copied by another contemporary, Judah ha-Kohen ben Tuviahu[4] who had close relations with Maimonides himself, and even sent him a letter of congratulations on his marriage.[5] Based on these examples I think it becomes clearer that Maimonides was in fact familiar with Rashi’s commentary ­— at least to some extent.

Upon a second reading of the fragment, I noticed that it also cites another commentator, known to us from book lists[6] found in the Genizah — Joseph ben Yahaboy. From the book lists we learn that he wrote commentaries to various tractates of the Talmud.[7] Based on these mentions it seems that his commentaries were not so rare, and we can assume that fragments of his commentaries are scattered in the Genizah and still await to be identified. Traces of his commentaries are cited in other documents from the Genizah: in a comment, by the hand of Hananel ben Samuel, written on the margins of an anonymous commentary to Eruvin,[8] Hananel referred to Joseph ben Yahaboy’s interpretation of the term שיחור in tractate Gittin 19a: ובן יהבוי פסרה כמא פסרה אלערוך וקאל כלי ברזל הו שלברזל (and ben Yahboy interpreted it as the ‘Arukh had interpreted it …).[9] In another Genizah manuscript, T-S F3.27, a commentary to Baba Mezi’a, Joseph ben Yahaboy is mentioned twice.[10]  

Who was this Joseph ben Yahaboy and when did he live? The Genizah documents reveal some information about his time and place. Rabbi Joseph ben Yahaboy is mentioned in T-S 24.18,[11] l. 30, 34, a fragmentary copy of an undated court record, one of four records from al-Mahdiyya and Qayrawan, two of which are dated 1049 and 1055 respectively. From this document, we can assume that he was active in North Africa, around the middle of the 11th century.

In ENA 4009.9, the same name is mentioned twice. In both cases the name יהבוי is corrected fromיעקב  and the reason for the correction is not clear. The date is only partially preserved: ‘Marheshvan […] thirty two to the date of the Arabs’, which can be either 432 Hijri (= 1040) or 532 (= 1137). It reads in l. 5: ראש ישי]בת גאון יעקב ביר אברהם; this Head of the Yeshiva might be Nathan b. Abraham, whose rivalry with Solomon b. Judah took place between 1034–1042, so the year 1040 is more likely.[12]


Back to our fragment, which concerns the different kind of inks to be used for writing a bill of divorce. In the lines I have copied below, the anonymous commentator cites an extract from Joseph ben Yahaboy’s commentary to Giṭṭin 19a alongside the commentaries of Maimonides and Rashi, who interpret the same technical terms. Joseph ben Yahaboy's explanation for the term מי טריא is unique: he explains טריא as derived from the Greek τρία “three”, that is, an ink made of three ingredients.



2            בסם פיר' ר' יוסף ביר' יהבוי עק[...] מע[...]ע/פ?י

3            ענדהם פי דלך אלזמאן בדיו פ[...]דה[..]ה באלסיקרא

4            פיר' אלמגרה בקומוס פיר' אלצמג בקלקנתוס והו

5            צבג אלאסאכפה וקיל אנה אלזאג ובכל דבר שהוא

6            רושם פיר' לאיתויי מי טריא ואפצא פיר' טריא בלשון

7            יוון שלשה והו אלמתלת דיו שלשלשה סמנין והו אלחבר

8            עד כאן דבריו ז'ל' ורבינו משה פיר' קומוס אלזאג וק

9            וקלקנתוס אלקלקנת והו נוע מן אלזאג ור' שלמה ז'ל'

10          פיר' קלקנת[ו]ס שרף האילן ומי טריא מים ששורה

11          בהן פרי שהוא כעין עפצים






I wish to thank Prof. M.A .Friedman, Dr Ezra Chwat and Dr Julia Krivoruchko for their helpful comments.

The research for this article was supported by the Fritz Thyssen Stiftung.


[1]  H. Fox, "Maimonides on Aging and the Aged in Light of the Esoterist-Harmonist Debate," in: Ira Robinson, Lawrence Kaplan, Julien Bauer, eds.,  The Thought of Moses Maimonides, Philosophical and Legal Studies (Lewiston 1990), p. 376.

[2] S. Friedman, “Maimonides’ Use of Rashi’s Commentaries: A Reevaluation,” in: Avraham Grossman, et al., eds., Rashi, the Man and his Works (Jerusalem, 2008), 403-464 (Hebrew).

[3] For one such list see T-S NS J126 [formerly T-S NS J94.126], published by Allony, The Jewish Library (Hebrew), no. 114, l. 108.

[4] E.g. T-S NS 329.723.

[5] JTSL MS 8254.16 (published by M.A. Friedman, ‘Two Maimonidean Letters: From Maimonides to R. Samuel the Sage; to Maimonides on his Marriage’ [Hebrew], in: Me'ah She'arim: Studies in Medieval Jewish Spiritual Life in Memory of Isadore Twersky, 2001, pp. 191-221. The writer was not identified there).

[6] See, e.g. T-S Ar.39.491, l. 6 (published by Allony, The Jewish Library, p. 72-74), and in the index, ibid.

[7]  His commentary to Gittin is mentioned in one book list written by Joseph Rosh ha-Seder, T-S K6.170, l. 10, published in Allony, The Jewish Library, p. 358 and in DK 123g (currently M62), published ibid. p. 403.

[8] Bodl. MS Heb. d.54/56 verso. The identification of the margins as written by Hananel ben Samuel was made by Dan Greenberger on the FGP website.

[9] This interpretation is found in the  'Arukh ha-Shalem, vol. 8, p. 57.

[10] Published by Ginzberg in Ginzei Schechter, II, p. 386, l. 10, p. 390, l. 9. Ginzberg (p. 382) reads here יוסף בר' יהסוי and יהכוי respectively, and suggests that the copyist may have erred in copying בר'מ' הלוי (מ' [=מאיר] הלוי), that is Joseph ben Meir Ibn Migash. The reading, however, is clearly יהבוי in both instances, as noticed already by Assaf, Kiryat Sefer, 22 (1945), p. 241, n. 1. He is also mentioned in other commentaries not from the Genizah, see the note to line 6 in Allony, The Jewish Library, p. 73, in the name of S. Abramson.

[11] Published together with T-S 12.634 in Gil, In the Kingdom of Ishmael, vol. 4, no. 818.

[12] ENA 4009.9 is referred to in M. Gil, Palestine during the First Muslim Period (634–1099) (Hebrew), vol. 1, p. 224, where he described it as a legal deed from al-Mahdiyya written in the hand of the famous Judah ha-Kohen ben Joseph, known as ‘the Rav’, who was active in Sijilmasa around 1050s–1060s. However, al-Mahdiyya is not mentioned, and it is not his hand, as evident, for example, from T-S G1.5a (+T-S 12.397 + T-S AS 155.329), where he signed (published by M. A. Friedman, ‘A Responsum by the “Rav” Judah b. Joseph ha-Kohen Concerning a Child Bride who Committed Adultery’, in: Diné Israel, 20–21 (2001) [Hebrew], pp. 329–351.


Cite this article

Ashur, A. (2019). On Rashi, Maimonides and a lost Talmudic commentator - Joseph ben Yahaboy: T-S Ar. 49.163. [Genizah Research Unit, Fragment of the Month, May 2019].

(This article was amended on 10 Sept 2021 to add further information about the estimated date of Yahaboy.)

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