In about 1000 C.E. the Ashkenazic halachic authority Rabbeinu Gershom of Mainz issued a decree called "Cherem de'Rabbeinu Gershom" banning bigamy. To prevent this decree from causing flippant divorces previously unnecessary, he also decreed that "a woman may not be divorced against her will." In certain extreme cases, however, such as the case of a man whose wife is missing, or refuses to accept a get for an extended period, Beth din will only permit him to remarry after one hundred rabbis agree with them to issue an exemption.