In the US it was most noticeable with the Mormans as they moved to Utah. The trip was long and many perished. There were a lot of women who had lost husbands. The goal of the Mormans was to colonize and flourish. The widows would have perished too without someone to protect them and provide for them. The surviving men agreed to take the widows on as another wife, even if they had children knowing that the more pregnancies they had the better for the health of the colony.