Mohammed is known by his biography, the Sira, and his traditions, the Hadith. There is no mention of him in historical records of his day. It is strange that a man could become the first ruler of a unified Arabia and not have any notice by anyone outside of Islam. He is mentioned four times by name in the Koran. Instead he is frequently referred by the titles Messenger and Prophet. Islam calls him the final prophet.
He was an orphan who became a successful businessman. In his forties he reported that he had visions and voices by the archangel, Gabriel, that brought him the words of the only god of the universe, Allah. The reported words were recorded in memory and written forms were called the Koran.
The Koran says in over 90 verses that Mohammed is the most perfect man who has lived and that he is the divine human prototype for all of humanity.
A brief summary of Mohammed’s career is that he preached the religion of Islam for 13 years in Mecca and converted 150 Arabs to Islam. He was a divisive man and the Meccans drove him out of town. He went to Medina and became a politician and jihadist. During the last 9 years of his life, he averaged a jihad event every 6 weeks. When he died in 632 CE, every Arab had converted to Islam due to jihad.
Mohammed was the most successful warrior in history. All other military leaders’ influence stopped after their death, but Mohammed has inspired war for 1400 years and it continues today. He was also the most successful law giver. His legal code, the Sharia, is the oldest active form of law.