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.
Muhammad
At the age of 25, Muhammad married the wealthy Khadijah bint Khuwaylid who was 40 years old. The marriage lasted for 25 years and was a happy one. Muhammad did not enter into marriage with another woman during this marriage. After Khadijah's death, Khawla bint Hakim suggested to Muhammad that he should marry Sawda bint Zama, a Muslim widow, or Aisha, daughter of Um Ruman and Abu Bakr of Mecca. Muhammad is said to have asked for arrangements to marry both. Muhammad's marriages after the death of Khadijah were contracted mostly for political or humanitarian reasons. The women were either widows of Muslims killed in battle and had been left without a protector, or belonged to important families or clans whom it was necessary to honor and strengthen alliances with.