It should be noted, however, that
conubium existed only between a
civis Romanus and a
civis Romana (that is, between a male Roman citizen and a female Roman citizen), so that a marriage between two Roman males (or with a slave) would have no legal standing in Roman law (apart, presumably, from the arbitrary will of the emperor in the two aforementioned cases).
[53] Furthermore, according to Susan Treggiari, "
matrimonium was then an institution involving a mother,
mater. The idea implicit in the word is that a man took a woman in marriage,
in matrimonium ducere, so that he might have children by her."
[54] Still, the lack of legal validity notwithstanding, there is a consensus among modern historians that same-sex relationships existed in ancient Rome, but the frequency and nature of "same-sex unions" during that period are obscure.
[55]
In 342 AD Christian emperors
Constantius II and
Constans issued a law in the
Theodosian Code (
C. Th. 9.7.3) prohibiting
same-sex marriage in Rome and ordering execution for those so married.
[56]