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
According to one account, after the last fort of the Jewish settlement called Khaybar was taken by Muhammad and his men, the chief of the Jews, called Kinana ibn al-Rabi, was asked by Muhammad to reveal the location of some hidden treasure. When he refused, Muhammad ordered a man to torture Kinana, and the man "kindled a fire with flint and steel on his chest until he was nearly dead." Kinana was then beheaded, and Muhammad took his young wife Safiyya as a concubine.