Following what the voices told him to do, Muhammad took parts of the Jewish and Christian faiths, of his time, and added new traditions and doctrines to it, creating Islam. He also wrote down revelations from the voices, writing them as the book known as the Qur'an.
By 622 AD, he had a substantial following, enough so that the city leaders plotted his assassination. Fleeing to Medina, he was granted a political position, and consolidated all power to himself.
In 629 AD, he led an army against Mecca, capturing the city, and beginning what would start more than a millennium of wars of conquest, in the name of spreading Islam.
At the time of Muhammad's death on June 8, 632 AD, he ruled much of what is now the Middle East, and his missionaries and armies were spreading further every year.
When European forces finally halted the armies of Islam, in 732 AD, the empire stretched from India to West Africa and the Iberian Peninsula.
Islam continued to spread through many means, through out the world. It is now the second largest religion in the world.
1,380 years after his death, Muhammad is still one of the most influential people in the world.