Bigamy

In countries that have bigamy laws, with a few exceptions (such as Egypt and Iran), consent from a prior spouse makes no difference to the legality of the second marriage, which is usually considered void.

Even before Christianity became the official religion of the Roman Empire, Diocletian and Maximian passed strict anti-polygamy laws in 285 AD that mandated monogamy as the only form of legal marital relationship, as had traditionally been the case in classical Greece and Rome.

[citation needed] In 393, the Roman Emperor Theodosius I issued an imperial edict to extend the ban on polygamy to Jewish communities.

In 1000, Rabbi Gershom ben Judah ruled polygamy inadmissible within Ashkenazi Jewish communities living in a Christian environment.

This is the case with the United States where the criminalisation of a polygamous lifestyle originated as anti-Mormon laws, although they are rarely enforced.