here is what wiki says on the issue:
For most of Western history, marriage was a private contract between two families. Until the 16th-century, Christian churches accepted the validity of a marriage on the basis of a couples declarations. If two people claimed that they had exchanged marital vowseven without witnessesthe Catholic Church accepted that they were validly married.
Some states in the US hold that public cohabitation can be sufficient evidence of a valid marriage. Marriage license application records from government authorities are widely available starting from the mid-19th century. Some are available dating from the 17th century in colonial America.[1] Marriage licenses have been required since 1639 in Massachusetts, with their use gradually expanding to other jurisdictions.[2] These prohibitions have changed throughout history. In the 1920s, they were used by 38 states to prohibit whites from marrying blacks, mulattos, Japanese, Chinese, Indians, Mongolians, Malays or Filipinos without a state approved license. At least 32 nations have established significant prohibitions on same-sex marriage.[3]
http://en.wikipedia.org/wiki/Marriage_license
So, as stated above, the licensing of marriage by the state is fairly recent concept. Throughout most of the history of western civilization, it was not licensed.
“So, as stated above, the licensing of marriage by the state is fairly recent concept. Throughout most of the history of western civilization, it was not licensed.”
I would add that defining and regulating marriage is not an enumerated power in the Constitution. Therefore, the debate over marriage should be taking place in the states and not the national level. In fact, the federal Defense of Marriage Act should be held unconstitutional by the Supreme Court based on Amendment X to the Constitution.