Fakhr al-Din al-Razi, whose full name was Abū ʿAbd Allāh Muḥammad ibn ʿUmar ibn al-Ḥusayn (Arabic : أبو عبد الله محمد بن عمر بن الحسين), was born in 1149 or 1150 CE (543 or 544 AH) in Ray (close to modern Tehran), whence his nisba al-Razi. According to Ibn al-Shaʿʿār al-Mawṣilī (died 1256), one of al-Razi's earliest biographers, his great-grandfather had been a rich merchant in Mecca. Either his great-grandfather or his grandfather migrated from Mecca to Tabaristan (a mountainous region located on the Caspian coast of northern Iran) in the 11th century, and some time after that the family settled in Ray. Having been born into a family of Meccan origin, al-Razi claimed descent from the first caliph Abu Bakr (c. 573–634), and was known by medieval biographers as al-Qurashī (a member of the Quraysh, the tribe of the prophet Muhammad to which also Abu Bakr belonged). However, it is not clear from which precise lines of descent al-Razi envisioned his purported ties with Abu Bakr to result, and the poet Ibn ʿUnayn (died 1233) actually praised him as a descendant of the second caliph Umar ibn al-Khattab (died 644).