Herodotus and Diodorus
The Greeks and Romans then too came up with a way to catalog cultures and groups of people. A group I found most interesting was The Men of the Island and the Sun. This group does not marry but does hold common wives, and they raise their children as if they belonged to all of them. When the children are babies, the nurses often change them around, so that not even the mothers know their own offspring. They do this to ensure that mothers are not obsessed with honor. Diodorus explains this as expanding the idea of sex with communal child-raising. This idea is fascinating to me because in some modern societies having a child can be a mother's greatest accomplishment and then that mother cares for her child and her child only. But in this culture, once mothers bear children they are responsible to care for all of society's children like they are their own because they have no idea which child they originally birthed.