Early jurists described marriage with the same vocabulary of ownership they used for slavery: forming a marriage was compared to a purchase, and ending one was compared to freeing a slave. Borrowing that language shaped what rights each spouse was thought to hold.
Once a husband was likened to a master and a wife to a slave, the comparison kept generating new rules in its own image. This happened even while the same jurists insisted that free women had dignity, so the analogy outran the scholars' stated intentions.
Marriage and slaveholding were formally distinct legal institutions, yet each molded the other's doctrines. Sometimes their rules converged and sometimes they deliberately diverged.
What a husband and a wife could demand of each other, such as dower, sex, obedience and companionship, was tied together and differed by sex. Each claim depended on the others, so debates about any one of them kept returning to questions of status: wife or concubine, slave or free, male or female.
When rules of sex and rules of ownership overlapped, the hierarchies did not line up neatly. A free woman who owned land could not have sex with her male slave, while that same slave might be allowed concubines of his own. Jurists increasingly defended enslaved husbands' masculine rights.