We read a lot in the culture wars about marriage, like it is a concept that has been around forever and everyone knows what it is. That isn't quite true. Marriage as we know it today, is a fairly recent invention. As recently as 500 years ago, few people in Europe bothered to get married. Only the landed classes tended to formalize marriage. There are many cultures that have or had no concept of marriage. Others practiced very different forms of marriage (think Muslim and Original Mormons).…