How do the environment and center-periphery power dynamics influence constructions and articulations of Muslim identity? This comparative historiographical paper examines the construction and expression of Muslim identity in two important physical peripheries: Persia and Anatolia. Prior to becoming important foci of Muslim piety and Islamic learning, Persia and Anatolia were considered physical and spiritual peripheries of the Islamic umma. This paper considers the effect environment, broadly construed – built, social, spatial, cultural, literary, and linguistic – on the construction and articulation of Muslim identities in Iran and Anatolia. This study also considers the impact of center-periphery relations on the construction and articulation of Muslim identities in what were originally the peripheries of the early Muslim empire. This paper assesses whether the tendencies so clearly seen in the Persian local histories, which articulate a spatio-communal identity centered on the twinned virtues of piety and religious authority, are also seen in Anatolian texts. Specifically, this project tests in Anatolian sources a hypothesis about differences of Muslim character of Arab and Persian cities. This hypothesis suggests that the ancientness of the Arab cities, coupled with their sizeable minority religious populations made the newer, smaller, Iranian cities seem more Muslim in comparison. This paper explores the character of the city in Anatolia, which is neither Arab nor Persian and forms a physical as well as metaphorical bridge between Central Europe and Western Asia. The advantage of considering these two regions for a comparative historiographical picture is because the process of Islamization occurred in Anatolia roughly 500 years after it happened in Iran. Anatolia serves as a testing ground for hypotheses about earlier Persian developments. This comparative historiographical project uses Arabic and Persian local and regional histories as well as chronicles of dynasties and the genre of literature about the Companions of the Prophet Muhammad. This paper builds on earlier research about the Islamization of Iranian cities during the 10th-13th centuries. These Persian sources include local and regional histories, such as Tarikh-i Sistan, Tarikh-i Tabaristan, Tarikh-i Bukhara, Tarikh-i Bayhaq, and Tarikh-i Qum, while Anatolian sources include local and regional histories as well as chronicles of dynasties and the genre of literature about the Companions of the Prophet Muhammad. This paper also problematizes the very notion of Iranian cities and Persian historiography, given the broad geographical range of texts that fall under the rubric of Persian cultural production.