This thesis follows Quṭb al‐Dīn al‐Shīrāzī (d. 1311), a brilliant and influential polymath, through the eighty years of his long life and focuses on him navigating changing environments in the Persianate Mongol world (i.e., the second half of the thirteenth century to the early decades of the fourteenth century). In order to retrace his life, this study draws extensively on contemporary chronicles, biographical dictionaries, autobiographies, hagiographies, and some of his own manuscripts to illuminate parts of his life unknown before. Through that, this thesis illustrates Quṭb al‐Dīn al‐Shīrāzī’s intellectual, political, and religious networks, with special attention to his patrons. Moreover, even though his fame in the modern world is primarily due to his astronomical treatises as part of the Maragha school, my thesis demonstrates his investment in medicine, Sufism, and religious sciences, including jurisprudence, Qurʼān interpretations, and ḥadīth studies. Hence, Quṭb al-Dīn is an example of an intellectual in the Ilkhanid realm who developed informal networks transcending political, linguistic, and genre boundaries, that spanned an area from the western fringes of Anatolia to Khorasan, through bustling late medieval metropolises such as Shiraz, Sivas, Konya, Baghdad, Cairo, Tabriz, and Maragha.