In this year died Muhammad, the leader and false prophet of the Saracens, after appointing his kinsman Abu Bakr to his chieftainship. At the same time his repute spread abroad and everyone was frightened. At the beginning of his advent the misguided Jews thought he was the Messiah who is awaited by them, so that some of their leaders joined him and accepted his religion while forsaking that of Moses, who saw God. Those who did so were ten in number, and they remained with him until his murder. But when they saw him eating camel meat, they realised that he was not the one they thought him to be, and were at a loss what to do; being afraid to abjure his religion, those wretched men taught him illicit things directed against us, Christians, and remained with him.
I consider it necessary to give an account of this man’s origins. He was descended from a very widespread tribe, that of Ishmael, son of Abraham; for Nizaros, descendant of Ishmael, is recognised as the father of them all. He begot two sons, Moudaros and Rabias. Moudaros begot Kourasos, Kaisos, Themimes, Asados and others unknown. All of them dwelt in the Midianite desert and kept cattle, themselves living in tents. There are also those farther away who are not of their tribe, but of that of Lektan, the so-called Amanites, that is Himerites. And some of them traded on their camels. Being destitute and an orphan, the aforesaid Muhammad decided to enter the service of a rich woman who was a relative of his, called Khandija, as a hired worker with a view to trading by camel in Egypt and Palestine. Little by little he became bolder and ingratiated himself with that woman, who was a widow, took her as a wife, and gained possession of her camels and her substance. Whenever he came to Palestine he consorted with Jews and Christians and sought from them certain scriptural matters. He was also afflicted with epilepsy. When his wife became aware of this, she was greatly distressed, inasmuch as she, a noblewoman, had married a man such as he, who was not only poor, but also an epileptic. He tried deceitfully to placate her by saying, ‘I keep seeing a vision of a certain angel called Gabriel, and being unable to bear his sight, I faint and fall down’.
Now, she had a certain monk living there, a friend of hers (who had been exiled for his depraved doctrine), and she related everything to him, including the angel’s name. Wishing to satisfy her, he said to her, ‘He has spoken the truth, for this is the angel who is sent to all the prophets.’ When she had heard the words of the false monk she was the first to believe in Muhammad and proclaim to other women of her tribe that he was a prophet. Thus, the report spread from women to men, and first to Abu Bakr, whom he left as his successor. This heresy prevailed in the region of Ethribos, in the last resort by war: at first secretly, for ten years, and by war another ten, and openly nine.
He taught his subjects that he who kills an enemy or is killed by an enemy goes to Paradise; and he said that this paradise was one of carnal eating and drinking and intercourse with women, and had a river of wine, honey and milk, and that the women were not like the ones down here, but different ones, and that the intercourse was long-lasting and the pleasure continuous; and other things full of stupidity. Also, that men should feel sympathy for one another and help those who are wronged. (From the Year 6122 (629/630 AD).
Taken from, Mango and Scott. The Chronicle of Theophanes the Confessor. pp. 464-65.