This book explores the way in which different ethnic, religious and linguistic communities co-existed and conflicted in the Roman Near East in the three centuries between the conversion of the Emperor Constantine to Christianity in 312 and the beginning of Muhammad's preaching in about 610. In the fourth century, a major role was played by Greek-speaking pagans, most notably the great orator, Libanius, from Antioch in Syria. After about 400, however, the public observance of pagan rituals died away under the pressure of Christianity. But the Greek language, as used in the Church, remained dominant. Pagan Aramaic is curiously invisible in this period, but the dialect of Aramaic used by Jews in Palestine is found in very extensive use, along with Hebrew, in a mass of religious literature. Outside Palestine, the most notable development in the culture of the region was the emergence of Syriac (a particular dialect and script of Aramaic) as a language of Christian culture and belief. ‘Syrians’ however were not a distinct ethnic group. The group which was most distinct from the others was made up of the unsettled and warlike peoples on the fringes of the Empire whom almost invariably, call ‘Arabs’, but who in Late Antiquity were far more often referred to as ‘Saracens’. By the end of the period, many of them had converted to Christianity. The major puzzle which the book poses is what is the relation between this process of conversion and the rise of Islam.