Mathew Kuefler ( The Manly Eunuch: Masculinity, Gender Ambiguity, and Christian Ideology in Late Antiquity (The Chicago Series on Sexuality, History, and Society) ) notes that the traditional Roman patria potestas , and the male sexual privileges associated with it, were already waning in the early empire. But Constantine gave the system a firm kick in the shins.

By earlier rules, women could not manage property themselves. A widow would have to have her property managed by a man, as long as she lived. During the second and third centuries, jurists admitted that this was merely customary, but only with Constantine did the rules begin to change. He passed a law that “permitted women of good character over the age of eighteen to control their own property, although they still seem to have had to retain legal guardians.” By the end of the century, women had gained the same rights as men over their property, and the tutela mulierum had disappeared completely. Further, legislation in 414 ordered that all contracts made by women be considered as binding.”

Constantine changed the rules of divorce to the advantage of women as well. Earlier, men had been able to “repudiate a marriage partner at will,” and they often gave up one wife to secure a more socially advantageous wife, or one of proven fertility. Constantine denounced divorce “for trivial reasons,” and specified the conditions under which a man could sue for divorce. Women, further, were allowed to sue for divorce from a murder, tomb robber, or medicamentarius - Kuefler thinks this means “an abortionist or poisoner.” She could not divorce a muliercularius , which Kuefler suggests is “a man who visited prostitutes,” but the law clearly treats this as a serious breach of marriage.

Finally, Kuefler suggests that Constantine was the first specifically to prohibit rape.