Sefer Or Zarua and the legend of Rabbi Amnon
A UNIQUELY IMPORTANT Hebrew manuscript at the Bibliotheca Rosenthaliana is a late thirteenth-century copy of the famous halakbic work Sefer Or Zarua by Rabbi Isaac ben Moses of Vienna (c. 1180 - c. 1250). It was from this manuscript, one of only two surviving medieval copies, that the first edition of the work was published in Zhytomir in 1862. The Or Zarua preserves one of the earliest, if not the very earliest version of the story of Rabbi Amnon. At the end of the laws concerning Rosh Ha-shanah, Rabbi Isaac of Vienna recorded in the name of Rabbi Ephraim of Bonn (1133 - after 1197) that a great and pious scholar in Mainz, Rabbi Amnon, had been the target of a conversion attempt by the local ruler. Under the continued enticement of the ruler, Rabbi Amnon once faltered in his steadfastness. He deeply regretted this momentary hesitation and henceforth refused to appear before the ruler, whereupon the latter ordered his mutilation. With his last ounce of strength Rabbi Amnon asked to be carried to the synagogue on Rosh Hashanah. When the cantor reached the Kedushah prayer, Rabbi Amnon interrupted him and recited the hymn u-netanneh tokef. He passed away immediately afterwards; three days later he appeared in a dream to Rabbi Kalonymos ben Rabbi Meshullam and taught him the hymn that has since become a regular component of the Rosh Hashanah liturgy for Ashkenazi and Italian Jewry.
Much has been written about this story, about whether or not Rabbi Amnon was a historical figure; about the liturgical-literary problem concerning the hymn, the text of which antedates the time in which Rabbi Amnon was supposed to have lived; and about the historical setting that gave birth to the story, all of which have been subject to scholarly inquiry.
The attribution of the story to Rabbi Ephraim of Bonn is of special relevance. Rabbi Ephraim was the author of a chronicle, Sefer Zekhirah, on the Crusades and other anti-Jewish persecutions; of liturgical poems, some of which commemorate the martyrdom of Jewish victims; and of a commentary on liturgical hymns. In a recent article Ivan Marcus has argued convincingly that the Amnon story reflects the social and cultural reality of Ashkenazi Jewry in the late twelfth century, the time of Rabbi Ephraim.  The connection between the contents of u-netanneh tokef and martyrology, however, is unclear. In u-netanneh tokef there are no references to events or circumstances in the story itself, and it is devoid of any allusions to martyrology. Also deserving scrutiny is the problem of tracing the route or transmission of the Rabbi Amnon story through the ages.
On the basis of a very limited and preliminary search, it seems that unlike the standard printed machzorim, medieval manuscripts did not routinely place the Rabbi Amnon story alongside unetanneh tokef. A. N. Z. Roth in his study mentions only one manuscript, a machzor (Jewish National and University Library, 8°3037, beginning of the fourteenth century) in which the commentary to u-netanneh tokef includes the story, although in a version different from the one in the Or Zarua.   Roth refers to a Hamburg manuscript, dated 1317, where u-netanneh tokef is identified as the silluk (a type of piyyut) of Rabbi Amnon, but without the story itself. In printed editions the story first appears in the Bologna 1540 Roman Machzor and in the Venice1600 Ashkenazi Machzor.
The occurrence in an edition of Selichot published in Prague in 1587. Of a somewhat different version of the Rabbi Amnon story from the one commonly circulating presents a surprising twist. In this source the story appears before the selichah ta shema, written by the previously mentioned Ephraim of Bonn. We are told that before he died as a result of the mutilation he had suffered, Rabbi Amnon composed two poerns, ta shenia and u-netanneh tokef. The chronicles Shalshelet Ha-kabbalah by Gedaliah ibn Yahya (1515 - 1578) and Tzemach David by the Prague rabbi and scholar David Ganz (1541-1613) also mention ta shema along with u-netanneh tokef as having been authored by Rabbi Amnon. In fact, on the basis of the content of ta shema it may make more sense to attach the Rabbi Amnon story to it than to connect it to u-netanneh tokif. 
Whether we find the story connected with ta shema or u-netanneh tokef or both, many literary and liturgical questions and problems remain. A search for versions of the Rabbi Amnon story in other manuscripts of the Or Zarua, in collections of stories, in liturgical commentaries and in machzor manuscripts as well as printed editions, may one day yield some solutions to the puzzles posed by this widely known martyrological story. For now, the Amsterdam manuscript of Sefer Or Zarua continues to serve as the starting point of all inquiry into the history of the story of Rabbi Amnon of Mainz.
 I.G.Marcus, 'Kiddushha-shembe-ashkenaz we-sippur Rabbi Amnon
mi-Magenza' in: I.M.Gafni et al., eds., Sanctity of Life and
Martyrdom: Studies in Memory ef Amir Yekutiel (Jerusalem 1992) P. 131-147
 A.N.Z.Roth, 'U-netanneh tokef ve-ha-ir Magenza, Hadoar 44, 36 (1964) p. 650-651.
 Menahem H. Schmelzer, 'Maaseh Rabbi Amnon ve-ha-selicha ta shema, Hadoar 44, 38 (1964) P. 734.
E.G. L. Schrijver, 'Some Light on the Amsterdam and London Manuscripts
of Isaak ben Moses of Vienna's "Or Zaru'a"', Bulletin of the
John Rylands University Library Manchester 73, 3 (1993).
E.E. Urbach, [Introduction to] Sefer Arugat Ha-bosem 4 (Jerusalem 1963) P. 40, n. 92.