Is it true Muhammad ordered the beheading of 400 to 600 men and had their women and children enslaved?

The Muslim historian Ibn Isḥaq, author of the first biography of Muhammad, describes the Battle of the Trench and its aftermath much as you have described them here. Muhammad was a political and military leader as well as a religious leader. Some ignorant Muslims are not aware of all the facts about their faith and their Prophet, but educated Muslims know that m execution and slavery were indeed part of the early history of Islam. (Just for the record, Judaism and Christianity, the two other great monotheistic religions to arise in the Middle East, also have large-scale bloodshed and slavery in their histories.)