Hello.

I was in the middle of a discussion with a friend, when the subject of the history of marriage arose. (Note: he has an extensive knowledge of religious history as a devout Evangelical Christian. I am an agnostic who has no historical training.)

I stated my belief that marriage is not an institution based on religious tradition, and that I believe that it existed long before it was associated with any religion.

He countered with the most interesting questions, which stumped me. /r/askhistorians, I need you to point me to legitimate resources to answer these:

1. Has not both religion and marriage existed from the beginning of civilization?
2. Has there been any societally accepted marriage practices both historically and around the world that have not been religious in nature and language?

Thank you.