The increasing number of archaeological excavations in the Persian Gulf littoral have revealed a “Long Eighth Century” representing a significant high point in settlement extension and economic prosperity, a development parallel to that of the more well-studied Red Sea during this period (Power 2012). Its characteristics included the growth of urban areas, a shift from pastoral nomadism to permanent settlement, and the increasing exploitation of environmental resources for reasons linked to trade as well as the subsistence of local populations. This paper is primarily an analysis of the origins of these developments, origins which stem both from the policies of the increasingly centralized caliphate and the strategies of Gulf communities in taking advantage of new opportunities. It relies on two sets of primary sources. One is the increasingly abundant archaeological data, especially that from Kazima in Kuwait (Kennet, at al 2012), Tawwaj on the Bushehr Peninsula (Carter et al 2006) and Kush in Ras al-Khaimah (Kennet 2004). The other is the corpus of texts used for early Islamic history, but with a particular approach. Historians have come to recognize that these texts from the Abbasid period present a vision of history characterized by anachronistic or ideology-driven assumptions, one of which is a high degree of wise, centralized command by the Rightly Guided Caliphs (Noth/Conrad 1994). This paper dismisses sources which display this centralizing tendency and privileges less-used material such as that found in ‘Awtabi’s Ansab al-Arab and recently edited volumes of Baladhuri’s Ansab al-Ashraf, as well as information in poetry and geographic texts which are occasionally relevant. The resulting picture is an expansion of the Arab population zone which preceded rather than was caused by the coming of state control. This not only complements archaeological data, but matches the reconstruction of Hoyland based entirely on non-Muslim sources (2015). The caliphate did not found the garrison towns of Basra and Tawwaj in empty land as traditionally thought, but gained influence and then the ability to administer existing populations, including by pursuing a policy of Bedouin settlement. At the same time, Gulf populations increased their prosperity by tapping local products and probably transit trade for the markets of the increasingly prosperous empire of the caliphs.