This article says
The case for an automatic association between Christianity and monogamy is weakened further by the fact that socially imposed monogamy was first established in ancient Greece and Rome, centuries before Christianity even existed. Greco-Roman laws prohibited any man from having more than one official wife at a time. It's true that forms of de-facto polygamy (e.g. concubinage, sex with slaves) continued to be tolerated in these societies. Nevertheless, anti-polygamy laws made Greco-Roman society relatively sexually egalitarian (Scheidel, 2009), because by preventing elite men from legally acquiring multiple wives, they improved the ability of lower-ranking men to acquire wives of their own. So by the time Christianity began spreading through the Roman Empire in the first centuries AD, monogamy was already well-established. But even though Christianity did not introduce socially imposed monogamy to the West, it did fully embrace this institution, and as noted above, it was this embracement that ultimately led to monogamy's spread throughout the Western world
That article says that Roman and Greek laws prohibited polygamy hundreds of years before Christianity. I want exact dates, and exact laws, and well, exact history on how that happens. I mean, as exact as possible.
I asked another question in political StackExchange
The question asks if monogamy happened due to democracy.
Democracy started in Athens. At what date?
Then, after (or before) that, are there any laws in Athens that declare polygamy illegal? If so, at what date?
I know that polygamy was already illegal in Rome and Greece far before Christianity. However, I want to know exactly when.