Lawrence O'Donnell explains how definition of marriage has changed

MSNBC host Lawrence O'Donnell on Thursday night countered the claim made by opponents of same sex marriage that marriage has always been between one man and one woman.

"The modern idea of marriage for love and the possible defiance of parental arranged marriage is only about two hundred years old," he explained. "Before the 1700s, the most popular and proven marriage type was one man and many women. In human history, one man and one woman is a very recent behavioral evolution."

O'Donnell noted that the Old Testament made numerous references to polygamy. King Solomon, for instance, was said to have seven hundred wives and three hundred concubines.

The Prophet Muhammad also practiced polygamy and having multiple wives is still legal in many parts of the Muslim world.

O'Donnell concluded by questioning why the "highly changeable institution of marriage" could not be opened up to same sex couples in loving relationships.

Watch video, courtesy of MSNBC, below:

Visit msnbc.com for breaking news, world news, and news about the economy