Pope Nicholas I described the marriage ceremony in an 866 letter to Boris I, King of the Bulgarians.

Our people, both men and women, when they make the marriage contracts do not wear on their heads bands of gold, of silver, or of any metal. After the betrothals, which are a promise of future marriage, with the consent of those who have made them and of those under whose authority they stand, certain agreements are struck. After the groom has betrothed the bride through a ring of fidelity which he puts as a pledge on her finger, and after the groom has given to her the dowry upon which both have agreed together with the written instrument containing the agreement, in the presence of persons invited from both sides, then, immediately or after a suitable interval, lest it be presumed that...