The present dissertation is a study of the Nabivamsa, "The Prophet's Lineage," the first biography of the Prophet Muhammad to be composed in Bangla, in the first half of the seventeenth century. A literary milestone in the multi-ethnic, multi-cultural history of Islam, it marks a significant contribution to Bangla's rich literary corpus, and became a canonical work for the late-medieval Islamic Bangla literary tradition. This hitherto little-studied text is used to examine the nature of Islamic expansion on Bengal's eastern frontier, addressing issues of religious competition, identity formation, and conversion. These were central concerns of the author, Saiyad Sultan (fl. 1615-1646), who was an important Sufi pir. By situating the Nabivamsa, on the one hand, in the literary traditions of medieval Islam -- historiographies, tales of the prophets, biographies and ascension narratives of the Prophet Muhammad -- and in local Bangla epic, puranic, and hagiographical traditions, on the other, the dissertation studies the processes of translation by which local cultural figures and Bangla literary forms are used to legitimate and root the Arabian Prophet of Islam in Bengal. In examining the life of a text across the subject-author-text-community continuum over a time-span of nearly four hundred years, the dissertation traces the Nabivamsa's trajectory from its manuscript circulation in southeast Bengal into the print era, investigating the author's legacy and the text's meaning in various publics of memory.