Some biographical notices about the poet Ab? Tamm?m ?ab?b ibn Aws al-???? (188/804-231/845) claim that he was born to a Christian family, but they give few details about the poet’s Christian upbringing or his conversion to Islam. Louis Cheikho, in Shu?ar?? al-Na?r?niyya ba?da l-Isl?m, examines the case for and against Ab? Tamm?m’s Christian origins. Among his arguments is that Ab? Tamm?m’s given name (ism) ?ab?b is common among Christians but uncommon among Muslims. While the name ?ab?b may have been popular among Christians in the early twentieth century, when Cheikho was writing, this is not a sufficient basis to assume that the name has always been more common among Christians than among Muslims. Naming trends change over time, and some personal names in Arabic were non-sectarian in previous centuries but are now used almost exclusively by one religious group. For example, the names ?asan, ‘Uthm?n, and `Abd al-Ra?m?n, are today rare among non-Muslims, but they are all attested as personal names of Christians in Ab? Tamm?m’s era. To test the claim that the personal name ?ab?b was common among Christians and uncommon among Muslims for the period in which Ab? Tamm?m lived, several Arabic biographical dictionaries compiled during or before the seventh Islamic century (thirteenth century AD) were examined, as well as two of Cheikho’s encyclopedic works. The search returned notices of 25 individuals named ?ab?b. All but two of them appear to have been Muslims, based on other information in their biographical notices. One has a brief notice that gives no information about his religion, and the last is Ab? Tamm?m. The strongest evidence that Ab? Tamm?m grew up in a Christian family is that his poems contain references to Christianity that appear to show firsthand knowledge of the religion, such as could be written only by an expert in interreligious disputation or someone who had practiced the Christian religion himself. Meanwhile, the strongest evidence that he converted to Islam is that, while the biographical anecdotes make no mention of him receiving an Islamic education in his youth, his name appears in the isnad of several ?ad?ths. Furthermore, the narrative of Ab? Tamm?m as a Muslim convert of humble origins fits the archetype of the poet as an outsider who has no claim to prestige except his poetic talents.