ABSTRACT
Islam was born in Arabia but spent some of its most formative developmental periods in former Byzantine and Sasanian territories. For that reason, Chapter 1 introduces those two empires in broad brush strokes. The Byzantine and Sasanian empires lay on the frontier of the Arabian Peninsula, and both had reached a crisis point in their own development and in their relations with each other, rendering them vulnerable to external shock. The shock came from the unexpected direction of Arabia. There, Muhammad had introduced a monotheistic faith that had familiar echoes of both Judaism and Christianity; it also contained themes of social justice that had a potentially powerful appeal to subjects of the two bordering empires.
