Marriage was an important institution in Byzantium, regulating partnership between people of different sex and legitimizing their offspring. It also had great social value: through marriage the man fulfilled his role, which was to continue his family line, and the woman fulfilled her purpose in life, which was motherhood. It was for these reasons that the Church blessed the union of couples.

Women’s position in society was confined to the home, and family structure gave the father the final say in all family matters, acknowledging him as the pater familias, as in Roman times. The result of this was that women of the time were not free to choose their own spouse. According to Justinian legislation, no wedding could take place without the father’s consent unless the bride was over twenty-five years old and still unmarried. The mother's opinion was not taken into account, except for a short period of time under Isaurian legislation, which declared that the consent of both parents was needed. A woman could only oppose her father’s will in choosing a husband if he was immoral and brutal.

When a woman or man reached the appropriate age they received marriage proposals via matchmaking; this role was played by an older man or woman, who was usually known and appreciated. The matchmaker would make ​​his approach and praise the persons in question, saying how good and beautiful they were, how good their families were and how well suited to each other they were, and would of course discuss the amount of dowry the groom would receive or the bride would give. For all these efforts the matchmaker was rewarded.
In the early Christian years only civil marriage was considered valid. Although religious weddings could be also performed, they were not recognized by the state. From the 9th century onwards, legislation by Leo the Wise established religious marriage as the only legitimate form of union.

There were certain limitations on getting married. First of all, Byzantine law decreed that the bride should be over twelve years old and the man fourteen (of parenting age). This did not stop many parents from marrying off their children younger, especially in the case of daughters. Significant age differences between husband and wife were not uncommon, above all in poor families who saw an advantageous marriage as a solution to their problems. The difference could be scandalous; yet regardless of Church restrictions on men over seventy and women over sixty getting married, such partnerships continued to be arranged.

Once religious marriage became the norm, the Church would only agree to bless unions between people of the same religion and social class. Marriages between the rich and the poor were generally avoided, and strictly forbidden between wards and guardians or to eunuchs, monks and first-degree relatives. There were also restrictions on the number of times a person could marry. Only first marriages were regarded as perfect. Second ones were tolerated by the Church after widowhood or divorce, but were not generally encouraged. Third marriage was seen as polygamy and forbidden by the Church, which imposed a penance of excommunication for three or four years. The only exception to this was when the spouse had no children and was under 40 years old.

Royal weddings were not subject to the restrictions of age, religion or doctrine applying to others, since such unions contributed to the establishment of relations and political or military agreements with other states. This meant that there were cases of marriage involving substantial age differences and young children: Stephen Miliutin, the 40-year-old king of Serbia, was married to Simonis, the 5-year-old daughter of Andronicus Palaeologus, while the 50-year old Andronicus I married Anna, 11 year-old daughter of the king of the Franks.

Before the wedding the couple spent a period of engagement (betrothal) that initially lasted for up to two years, but was shortened considerably after the era of Leo the Wise. This period was sacred and the fiancé had to respect his fiancée; he could not, under any circumstances, hurt her or take her by force, otherwise he was severely punished and could no longer marry her. The agreement between parents could be given simply, either orally or by signing a contract. Marriage contracts drawn up by a notary gave details of what the parents of the bride promised to pay for the dowry; what the groom would offer as a gift to the bride to support her if he died; and what would happen if one of the parties failed to keep their part of the deal. Betrothal was made official with an engagement ring. After that the fiancé could kiss his future bride, visit her house and offer her gifts like clothes, jewellery and money, depending on what he could afford and his position in society.
Getting married was a major event, and many Byzantine wedding customs had their roots in antiquity, containing all kinds of symbols for the changes the marriage would bring to the lives of the husband and wife to be.

Weddings always took place on a Sunday evening, but never during Lent, on major feast days or, according to popular superstition, in the month of May. Once the wedding date was set, the couple’s parents would send out invitations in the form of treats such as apples, lemons, cloves or nougats.

The last Thursday before the wedding was set aside for the pastopigion, a custom very like the present day Greek tradition of “making up the bride’s bed”. During this feast, the bridal room was decorated with precious fabrics, utensils, jewellery and flowers, so as to impress guests visiting the room. If decorations were lacking then they would be borrowed for this special day. The guest sang songs about the couple and the love they shared.

Everybody wore their very best to the wedding, where the colour black was forbidden. The bride was helped to dress by other women, and as in ancient times wore fine white garments embroidered with gold and jewels. She put makeup on her eyebrows, eyelashes and face, and even dyed her hair red. In keeping with Roman customs, on her wedding day she appeared covered from head to toe in a veil, which she lifted after the ceremony to show her face to the groom. He smartened himself up by cutting and trimming his beard, and it was not unusual for a groom to dye his hair and eyebrows, especially if he was rather old.

When the time for the wedding approached, musicians and guests with lighted torches in their hands would arrive at the bride's house. The nuptial procession to the church was held in a festive atmosphere with wedding songs. The couple was accompanied by relatives and friends throwing flowers and rosewater on them, just as on the return home. After the wedding ceremony the couple headed to the groom's house, where they were greeted by his mother, who led them to the bridal room. Men and women guests then sat separately at the feast; depending on how wealthy the two families were this involved all kinds of fine foods and drinks, music, song, dances, mime artists, theatre and so on, in a celebration that could go on for up to seven days. The day after the wedding began with members of the two families waking up the newlyweds.

Breaking off a marriage was not accepted by the church. However, divorce cases seem to have been relatively common in Byzantium. According to law at the time of the Comnenus dynasty, some of the main reasons for divorce were: the inability of a man to have children; attempted murder of one partner by the other; insanity lasting more than three years; absence of a partner for more than five years; the husband or wife joining a monastery of their own will; hatred of one partner towards the other; unfaithfulness, etc.