Paul Freedman, professor of history at Yale, opens this lecture from The Early Middle Ages, 284-1000 with the geography of the Arabian peninsula and the tribal society of the Bedouins, comparing their raiding culture to the Germanic tribes covered earlier in the course. He explains how weakened Byzantine and Persian defenses left an opening for Arab expansion. The second half turns to Mohammed himself, born around 570-580 and dead in 632, tracing his revelation of monotheism and his place as the last in a line of prophets shared with Judaism and Christianity. Freedman describes how Islam only gradually separated itself from those older faiths, a split that sped up after the flight to Medina in 622, and closes with the basic tenets of the new religion, setting up the conquests themselves for the next lecture.