There have been cultures throughout the entire world which have their own form of marriage. It's no more a Christian invention than the bow and arrow is an English invention. We're talking about concepts which humans innevitably come up with no matter where they are. To use the bow and arrow, again, as an example, it was invented by different peoples in different locations, none of whom had any contact with the other groups who also invented it. If you placed humans on another planet, sooner or later they would learn to cultivate electricity, learn the benefits of irrigation, and even come up with their own version of marriage.

Moreover, so what if marriage were a Christian invention? Christianity has adopted many pagan traditions yet we pagans do not say that they should not be practicing these acts (I don't have any qualms with the fact that many Christians light candles for the dead, for example). I am a witch and I am legally married. I see nothing wrong with using this word: marriage. You're arguing over linguistic semantics, Russ. The concept of what marriage represents from a legal standpoint has nothing to do with religion. The concept of what marriage represents from a religious standpoint has nothing to do with Christianity.