On this day, March 9, in 1820 the first White House wedding of a child of a president took place when Maria Monroe, the 17 -year old daughter of President James Monroe, married her first cousin Samuel Gouverneur. Samuel was the son of the sister of First Lady Elizabeth Monroe and was serving as President Monroe's private secretary. Nowadays 25 states prohibit the marriage of first cousins and several other states prohibit it unless the female is beyond reproductive age. However, marriage of first cousins has always been permitted in the District of Columbia where the White House is located.
The grandsons of Maria and Samuel Gouverneur eventually established the James Monroe Museum and Memorial Library in Fredericksburg, Virginia on the site of President James Monroe's the original law office.