Muhammad prevailed partly by his successes in warfare and the rich booty they brought to his Arab adherents, partly by his sweetness of disposition, the magnetism of his appearance and manner, and his gift for pouring out conceptions of God and religion and garbled versions of the Jewish Scriptures and Christian beliefs in rhyming couplets easily committed to memory. He united gradually under his sceptre, as a religious teacher and legist, all the clans of fighting men in Western Arabia; and, in search of greater spoil than the poverty-stricken peninsula of that day could afford, he marched northwards to convert the Roman world and the great kingdom of Persia to his new faith. Almost like another Moses, he died on the threshold of the promised land; for within a few years of his death (632 A.C.) the Arab armies had not only smashed the Byzantine rule over Syria but were pouring into Byzantine Egypt and were rapidly conquering for the Muhammadan faith the states of South-west, South and East Arabia, and the whole kingdom of Persia, to the very heart of Asia. In 640-2 Amr-bin-al-As (an early opponent and a later convert of Muhammad) invaded Egypt from Arabia; and he or his lieutenants pushed thence into Tripoli, and even into Fezzan. A little later (647-8), under Abdallah-bin-Abu-Sarh and Abdallah-bin-Zubeir, the Arabs invaded Tripoli, and fought with a Byzantine governor known as Gregory the Patrician, who had just before rebelled from Byzantium, and proclaimed himself Emperor of Africa, with his seat of government in central Tunisia. The battle lasted for days, but Gregory was overmastered by a ruse and killed. The Arabs pursued his defeated army into the heart of Tunisia, and even into Algeria. For a payment of 300 quintals of gold they agreed to evacuate Tunisia, but they left behind an agent or representative at Suffetula (the modern Sbeitla), which had been Gregory’s capital.