The link between polygamy and the dawn of agriculture.

I've answered this question before, here's my answer:

The dawn of agriculture brought about the practice of polygamy.

Polygamy is a state of marriage wherein a man or a woman has many spouses.

When agriculture became the way of live of humans, men wanted to have more than they currently have. They wanted to have more wives, more children, and more land to till. Thus, the practice of polygamy emerged.