In Genesis we read accounts of the patriarchs having a number of wives. When was the practice stopped? Are there any Biblical and/or Talmudic references to marriage being one man-one wife?
There is no biblical injunction against a man marrying more than one wife. As you point out, in the Torah, this was an accepted practice. Around 1000 years ago the leader of Ashkenaz world Jewery, Rabbeinu Gershom, instituted several bans that were accepted as law and remain in effect until today. Along with prohibiting one from reading another person’s mail and prohibiting a man from divorcing his wife against her will, he placed a ban on polygamy. This ban has been upheld and adhered to amongst Ashkenaz Jewery since the ban’s institution.
Rabbi Moshe Rosenstein