At the age of 40, in 610, Mohammed received his first revelation, a short text consisting of five verses. It is not clear precisely where he was when he had this first vision, but it clearly had an huge impact on him. He believed he had been in communication with mysterious forces. A handful of people began to believe in his prophecies: his wife; his best friend Abu Bakr; his cousin Ali; and a few foreign slaves. His tirades against the idols struck at the very foundations of Meccan trade. He was persecuted by the Qoreish tribespeople, who could not believe that God had chosen a person of modest social standing as His messenger, and refused to recognise him as a prophet. The Koran was to be revealed to Mohammed in groups of verses over the ensuing twenty-three years. It prescribed a monotheistic religion which incorporated the earlier messages on which Judaism and Christianity were based and presented itself as an extension of the Jewish and Christian belief-systems. In 622, following the death of his wife, at the end of a decade in which he suffered increasing intense persecution in Mecca, Mohammed ordered his followers to emigrate from Mecca to Yathrib, the future city of God, which he later renamed Medina. This exodus is known as the Hegira.