The study of Islamic rule in the former Sasanian lands has often concentrated on either the conquests or the circumstances for religious conversion. For those interested in the details of the formation and integration of Islamic power, scholars like Fred Donner or Hugh Kennedy have provided a comprehensive analysis of the wars of conquest based on textual sources. Scholars have also focused on the method and rate of conversion, e.g. Richard Bulliet, or the socio-religious consequences of conversion and its local responses, as most recently with Patricia Crone’s work or the fresh contribution by Sarah Bowen Savant. Less attention, however, is paid to small, fringe groups who managed to stay outside the political control of the nascent Islamic power. Their preservation of political independence, even for a short while, also meant a refusal to convert, and even a strong opposition to it. Among these independent local powers, the dynasties of the Sasanian province of Padishkhwargar – the south Caspian provinces of Tabaristan, Deylaman, and Gilan – present the most glaring examples. Early Bāvandids, and more importantly the Dabūyids, are characterized by a series of successful attempts at controlling the area, and to even exert power over the Alborz range in Qazvin and Ray. The present paper, then, will address the history of these polities and their role in diffusing Sasanian socio-cultural and political values to the Islamic polities that come to replace them. Specifically, attention will be paid to the continuity in the use of Middle Persian language – the language of the Sasanian administration but not the regional language – and traditions of kingship, agnatic relationship, religious continuity, and preservation of material culture. The paper will take advantage not only of written historical sources, but also material from archaeology, numismatics, as well as the newly discovered Pahlavi Archive of Tabaristan. It is believed that understanding the early Islamic history of Padishkhwargar will be central in presenting a full picture of the rise of subsequent Daylamite amd Tabari dynasties such as the Zayarids and the Buyids and their continued effect on mediaeval Islamic Iran.