born Nov. 3, 1798, Fairfax county, Va., U.S.
died April 28, 1871, Alexandria, Va.
U.S. politician.
A grandson of George Mason , he practiced law in his native Virginia from 1820. He served in the state legislature (1826, 182832), the U.S. House of Representatives (183739), and the U.S. Senate (184761). An advocate of secession, he resigned his Senate seat in 1861. Appointed Confederate commissioner to England, he was captured at sea with John Slidell aboard the Trent and imprisoned for two months (see Trent Affair ). Released in 1862, he remained in England until 1865 but was unable to win support for the Confederate cause.