Many of the OT texts, especially in the Pentateuch and the Deuteronomistic history, depict households with one man and multiple adult women. This marriage pattern is polygyny, a type of polygamy in which there are multiple women. This pattern maximizes fertility rates, while tending to favor the political power of the sole male as leader of the household. It is not known if polygynous households were the norm in Israel or if they occurred only among the wealthier households, such as those that are more frequently represented in the extant literature. When polygyny did occur, it is likely that the women were of different ages. The household may have begun with one man and one woman, adding other women as the financial resources of the household expanded. Women's life expectancy was much shorter than that for men, and pregnancy was among the leading causes of death for Israelite women. In this situation, polygyny became a way to maintain the supply of women in the household as well as to increase its fertility. If the man of the household outlived the first wife by many years, then there may have been a great age difference between the man of the household and subsequent wives. Such a version of polygyny shares some parallels with sequential marriages.