In the historiography of the early Islamic Conquests, there as an artificial division assumed between the conquests themselves and the military events that preceded them, namely the Sasanian conquest of the Eastern Mediterranean in 602-630 and the Byzantine responses to it. While the role of the Arabs of the Levant is sometimes considered as far as they relate to imperial policies of the Sasanians and the Byzantines, their role as the population of the war zone is commonly ignored. Similarly, the population of the Hijaz are seen as somehow standing outside the context of the Sasanian-Byzantine conflicts, only coming to "take advantage" of the situation following the collapse of the Sasanians and the loss of Byzantine territories in Syria and Egypt. The present paper sets out to view both sides of the artificial divide of "the Rise of Islam" from the point of view of local actors. Relying on new, closer readings of the Islamic histories and considering Armenian, Syriac, Greek, and Persian accounts, as well as the evidence of numismatics and archaeology, it aims to see the events of the period 602- 647 (the first phase of the conquests) as a coherent and connected set of events. It does this by concentrating on the fighting forces of the Sasanians on their desert frontier along the lower Euphrates and westward to Palestine. The hypothesis of the paper is that various forces fighting on behalf of the Sasanians, evolved into local warlords and forces, controlling the conquered land, and eventually joining, and becoming a major component of what we label "the Conquering Islamic Armies". In this sense, the paper will also make contributions to the debate over the name of the Conquests themselves as far as their sobriquet of "Arab", "Muslim" or "Islamic" is concerned.