"Heter Meah Rabbonim" is a vehicle utilized to circumvent the general prohibition against polygamy. Relying on the principle of endeavoring to prevent matrimonial strife (which principle had already been well developed in talmudic law) Rabbenu Gershom b. Judah and his court enacted the takkanah prohibiting a man from marrying an additional wife unless specifically permitted to do so on special grounds by at least 100 rabbis from three "countries." This takkanah, known as the Herem de-Rabbenu Gershom, also prohibited a husband from divorcing his wife against her will. Estranged husbands have on occasion attempted to use the heter as a method of receiving permission to marry a second wife.