Muhammad's wives
Muhammad was monogamous for 25 years. After his first wife Khadija bint Khuwaylid died, he proceeded to marry the wives listed below, and most of them were widows. Muhammad's life is traditionally delineated as two epochs: pre-hijra (emigration) in Mecca, a city in western Arabia, from the year 570 to 622, and post-hijra in Medina, from 622 until his death in 632. All but two of his marriages were contracted after the Hijra (migration to Medina). Of Muhammad's thirteen wives, at least two, Rayhana bint Zayd and Maria al-Qibtiyya, were referred to simply as concubines; however, there is debate among Muslims as to whether these two officially became his wives. Of his thirteen wives, only two bore him children, a fact which has been described as "curious" by Cornell University Professor of Near Eastern Studies David S. Powers.
Criticism of Muhammad
Some Western thinkers and Christian evangelicals criticize Muhammad for having had a child (Ibrahim, who died in infancy) by a slave girl called Maria al-Qibtiyya, one of his concubines who was a present from the Christian Byzantine ruler of Egypt. Sources, including Ibn Qayyim Al-Jawziyya claim that she was a concubine and not a slave. She is also not mentioned in Ibn-Hisham's notes on Ibn-Ishaq's biography where he lists the wives of Muhammad. According to a hadith, Muhammad left no slaves at the time of his death.