What we call the Early Middle Ages were a period of transition and integration between Roman, Christian, and “barbarian” marriage customs. While it isn’t possible to speak of any definitive legal code in this time period, most legal writings began emphasizing the consent of the individuals actually getting married over that of their families, though it’s unlikely these opinions had much practical force. The question of consummation and whether it was important as consent also began to come up.
By the 12th and 13th centuries, lawyers, in particular Gratian and those who followed him, were attempting to clarify and strengthen the Church’s position on these things, particularly on what constituted consent or a defect therein. Defects in consent included concealing one’s identity from one’s spouse, being underage, insanity, or the concealment of heretical beliefs.** The consent of parents was held to be important but not legally essential.* Gratian held consummation to be as important as consent, though this was a less defensible position, considering that the Virgin Mary and St. Joseph were believed never to have consummated their marriage.
Over the course of a millennium, consent became more and more essential, while its definition became more refined. The debate about consummation continued for centuries, with points scored on both sides. It’s important to remember though that this only tells part of the story. What happened in practice did not always match up with lawyers’ arguments.
*What the law said was not always what people actually did. In Ancient Rome, for example, though consent was the only thing legally required, social custom required a dowry and the enactment of various ceremonies. These were equally important, but not legally required. In medieval Europe, parental consent became less essential legally while still retaining its social importance.
**Some lawyers also argued that it was impossible for a woman to consent to marry her rapist and forbade any such marriage from taking place. Gratian disagreed, arguing that she and her family could consent but only if the rapist repented and did penance.
Brundage, James A. Law, Sex, and Christian Society in Medieval Europe. Chicago: University of Chicago Press, 1987.
Marriage and Divorce - Consistory Database
Marriage Canons in The Decretum of Gratian - Catholic University of America