According to Muslim tradition, Muhammad's wife Khadija was the first to believe he was a prophet. She was followed by Muhammad's ten-year-old cousin Ali ibn Abi Talib, close friend Abu Bakr, and adopted son Zaid. Around 613, Muhammad began to preach to the public (Quran 26:214). Most Meccans ignored and mocked him, though a few became his followers. There were three main groups of early converts to Islam: younger brothers and sons of great merchants; people who had fallen out of the first rank in their tribe or failed to attain it; and the weak, mostly unprotected foreigners.