Muhammad and Polygamy

Muhammad did not introduce polygamy:

In fact polygamy existed before Islam without any limit in number. It was very common for a man to have more than one woman either as wives or as concubines or slaves. It is known that Prophet Abraham was married to Sara, the mother of Isaac and Hagar, the mother of Ishmael. Also, it is narrated that Jacob had four women, two wives and two concubines.