Polygamy was such a well established part of the social system that Mosaic law is not even critical of it. We find only certain regulations with respect to it; as, for example, if a man takes a second wife the economic position of the first wife and of the children she bore must be secure; and, in the case of inheritance, no child of a subsequent marriage is to be preferred over a child from the first wife. Other regulations were that the high priest could have only one wife and that a king in Israel should not have too many wives (Lev. 21:13; Deut. 17:17; Ex. 21:10). The last injunction, however, was of no effect. David had seven wives before he began to reign in Jerusalem, and an extraordinary number of wives and concubines has been attributed to Solomon (II Sam 3:2-5, 14; 5:13). In connection with David, the prophet Nathan did not denounce the king for adding Uriah's wife to those he already had but for the means he employed to secure her (II Sam. 12:7-15).

However, if polygamy was not forbidden it was not directly sanctioned. It was a heritage from the past and it was left undisturbed. As the civilization of the people reached a higher form and, especially under the teaching of the prophets, their moral and religious consciousness developed, the polygamous system gradually declined. This is noticeable in Israel after the return from the Exile. In the Second Commonwealth polygamy is far from general (cf. Tobit and Susanna). Yet it survived far into the Christian era. In the New Testament Jesus neither condemns polygamous unions nor advocates a change in the system. From this noninterference attitude Luther, as late as the 16th cent., arrived at the conclusion that he could not forbid the taking of more than one wife.

According to the Talmud the right to a plurality of wives is conceded, but the number of legitimate wives, as in the Koran, is limited to four. The taking of additional wives is held as sufficient ground for divorce for a woman who had previously been the sole wife. Where a polygamous union exists, provision must be made for adequate maintenance of each wife as well as a separate domicile. Throughout the Talmudic age not one rabbi is known to have had more than one wife. Monogamy was held to be the only ideal legal union; plurality of wives was a concession to time and condition.

At a later period Maimonides in his Mishneh Torah maintains, contrary to his personal opinion, that polygamous unions from a strictly legal point of view are permissible. Eventually, however, they were proscribed under the authority of Rabbi Gershom (about l000), although cases of polygamy were found in Spain as late as the 14th cent. That such cases were not rare may be inferred from the fact that in the Spanish communities the Kethubah, the document marking the betrothal, exacted that the man was not to take a second wife. The Islamic influence on the Jews in Spain was more or less pronounced until the expulsion at the end of the 15th cent.

In modern Europe polygamy disappeared from Jewish domestic life while among Christians it remained a tolerated privilege of royalty until very late times. In the declaration against polygamy of the Sanhedrin convoked by Napoleon in Paris, in 1805, there is no implication that modern Judaism tolerated plural marriages. It was just an emphatic assertion that Jews had discarded the orientalism of the past and were in full accord with the culture and civilization of Western Europe.