for those interested in a more historical perspective of 'marriage' I'll add the following:
Marriage as a Ceremony or Contract
The act, formality, or ceremony by which the marriage union is created, has differed widely at different times and among different peoples. One of the earliest and most frequent customs associated with the entrance into marriage was the capture of the woman by her intended husband, usually from another tribe than that to which he himself belonged. Among most primitive peoples this act seems to have been regarded rather as a means of getting a wife, than as the formation of the marriage union itself. The latter subsequent to the capture, and was generally devoid of any formality whatever, beyond mere cohabitation. But the symbolic seizure of wives continued in many places long after the reality had ceased. It still exits among some races, and until quite recently was not unknown in some parts of Eastern Europe.
After the practice has become simulated instead of actual, it was frequently looked upon as either the whole of the marriage ceremony or an essential accompaniment of the marriage. Symbolic capture has largely given way to wife purchase, which seems to prevail among most uncivilized peoples today. It has assumed various forms.
Sometimes the man desiring a wife gave one of his kinswomen in exchange; sometimes he served for a period his intended bride's father, which was a frequent custom among the ancient Hebrews; but most often the bride was paid for in money or some form of property.
Like capture, purchase became after a time among many peoples a symbol to signify the taking of a wife and the formation of the marriage union. Sometimes, however, it was merely an accompanying ceremony. Various other ceremonial forms have accompanied or constituted the entrance upon the marriage relation, the most common of which was some kind of feast; yet among many uncivilized peoples marriage has taken place, and still takes place, without any formal ceremony whatever.
By most civilised races today, the marriage ceremony is regarded as a religious rite or includes religious features, although the religious element is not always regarded as necessary to the validity of the union. Under the Christian dispensation marriage is a religious act of the very highest kind, namely, one of the seven sacraments. Although Luther declared that marriage was not a sacrament but a "worldly thing", all the Protestant sects have continued to regard it as religious in the sense that it ought normally to be contracted in the presence of a clergyman.
Owing to the influence of the Lutheran view and of the French Revolution, civil marriage has been instituted in almost all the countries of Europe and North America, as well as in some of the states of South America. In some countries it is essential to the validity of the union before the civil law, while in others, e.g., in the United States, it is merely one of the ways in which marriage may be contracted. Civil marriage, for all intents and perposes is a post-Reformation European institution that spread to other countries with christianity .