It is perhaps interesting to note that in Europe (and I imagine elsewhere to a certain extent) Marriage was a financial matter. Making sure a marriage was legal, recognsed and binding was vital for the rich and powerful because of inheritance and such. For the poor, with little posessions, marriage was a far more informal business.
Before the eleventh century, marriage was strictly business. Because power and kingship (in the Germanic world) was not regulated by primogeniture (first-born right), but by power-struggles within the royal family, bigamy was not uncommon. Charlemagne had several wives at once. He also allowed his daughters as many lovers as they wished, but no marriages, as husbands could try a claim for the throne, as lovers could not.
In the eleventh century, the church began a reorm program designed to give the popes in Rome more power over the institute of the church. One of their main points was stricter regulation of peoples private lives through enforcement of clerical celibacy (considered as optional before) and the enforcement of official marriage. It is from this time onwards that marriage was considered a sacrement and church business, instead of a private one.