George Mason IV (December 11, 1725 – October 7, 1792) was an American Patriot, statesman and a delegate from Virginia to the U.S. Constitutional Convention.is efforts eventually succeeded in convincing the Federalists to add the first 10 amendments of the Constitution. These amendments, collectively known as the Bill of Rights, were based on the earlier Virginia Declaration of Rights, which Mason had drafted in 1776. On the issue of slavery, Mason walked a fine line.