George Mason (December 11, 1725 – October 7, 1792) was a United States patriot, statesman, and delegate from Virginia to the U.S. Constitutional Convention. He is called the "Father of the Bill of Rights". For all of these reasons he is considered to be one of the "Founding Fathers" of the United States.
Mason wrote the Virginia Declaration of Rights, which detailed specific rights of citizens. In addition to anti-federalist Patrick Henry, he was later a leader of those who pressed for the addition of explicitly stated individual rights as part of the U.S. Constitution, and did not sign the document mainly because it did not contain such a statement. His efforts eventually succeeded in convincing the Federalists to modify the Constitution and add the Bill of Rights (the first ten amendments of the Constitution). The Bill of Rights is based on Mason's earlier Virginia Declaration of Rights.
Although a slave owner, Mason favored the abolition of the slave trade. He once referred to slavery as "that slow poison, which is daily contaminating the minds and morals of our people." However, he spoke out against including any mention of slavery in the Constitution--whether from an abolitionist or anti-abolitionist standpoint. 
George Mason was born on December 11, 1725, at the Mason family plantation in Fairfax County, Virginia. His father died in 1735 in a boating accident on the Potomac when the boat capsized and his father drowned. On April 4, 1750, he married sixteen-year-old Ann Eilbeck, from a plantation in Charles County, Maryland. They lived in a house on George's property in Dogue's Neck, Virginia. Mason completed construction of Gunston Hall, a plantation house on the Potomac River, in 1759. He and his wife had twelve children, nine of whom survived to adulthood. Mason's first child, Frank Mason V of Lexington, was born on April 30, 1753. He married Elizabeth Mary Ann Barnes Hooe (Betsy) on April 22, 1784, and after having six children, died on December 5, 1796. The next Mason offspring was Ann Eilbeck Mason, fondly known as Nancy. Born on January 13, 1755, she married Rinaldo Johnson on February 4, 1789 and had three children before dying in 1814. The third child was named William Mason, but he did not live over a year and died in 1757. The fourth child, born on October 22, 1757, was also named William Mason, and he married Ann Stewart on July 11, 1793. They had five children together, and he died in 1818. The fifth child was a son they named Thomson Mason. He was born on March 4, 1759 and died on March 11, 1820. Thomson married Sarah McCarty Chichester of Newington in 1784; they had eight children.
George Mason's sixth child, christened Sarah Eilbeck Mason but fondly known as Sally, was born on December 11, 1760 and married in 1778. She had ten children with her husband Daniel McCarty, Jr. before dying on September 11, 1823. The seventh of the Mason children was another girl, Mary Thomson Mason. She was born on January 24, 1764, and married John Travers Cooke on November 18, 1784, with whom she had ten children before dying in 1806. John Mason was Mason's eighth child, being born on April 4, 1766. He married Anna Marie Murray on February 14, 1796, had ten children, and died on March 19, 1849. The ninth child was a daughter named Elizabeth Mason. She was born on April 19, 1768 and died sometime between 1792 and June of 1797. She married William Thornton in 1789 and they had two children. The tenth child, Thomas Mason, was born on May 1, 1770 and died on September 18, 1800. He married Sarah Barnes Hooe on April 22, 1793 and the two had four children together.
George Mason's last two children were James and Richard Mason; twins who were born in December, 1772 but died six weeks later. Their mother died three months later on March 9, 1773 due to complications. George Mason remarried on April 11, 1780 but did not have any children with his new wife, Sarah Brent. George Mason also suffered from the condition known as gout for a large part of his life, and in accordance with current medical treatment, relied upon bloodletting.
Mason served at the Virginia Convention in Williamsburg in 1776. During this time he created drafts of the first declaration of rights and state constitution in the Colonies. Both were adopted after committee alterations; the Virginia Declaration of Rights was adopted June 12, 1776, and the Virginia Constitution was adopted June 29, 1776.
Mason was appointed in 1786 to represent Virginia as a delegate to a Federal Convention, to meet in Philadelphia for the purpose of revising the Articles of Confederation. He served at the Federal Convention in Philadelphia from May to September 1787 and contributed significantly to the formation of the Constitution. However, he would not sign the Constitution for a number of reasons; the very first of which was his objection that the original Constitution failed to contain a "declaration of rights". Mason continued to agitate for the addition of a bill of rights to the Constitution after the convention. This agitation cost Mason his long friendship with George Washington, and is probably a leading reason why George Mason became less well-known than other U.S. founding fathers in later years. On December 15, 1791, the U.S. Bill of Rights, based primarily on George Mason's Virginia Declaration of Rights, was ratified in response to the agitation of Mason and others.
Mason died at his home, Gunston Hall, on October 7, 1792. Gunston Hall, located in Mason Neck, Virginia, is now a tourist attraction. The George Mason Memorial is located in East Potomac Park, Washington, D.C., near the Thomas Jefferson Memorial; it was dedicated on April 9, 2002. A major bridge connecting Washington, DC, to Virginia is officially named the George Mason Memorial Bridge (it is part of the 14th Street bridge complex). George Mason University located in Fairfax, Virginia, is named in his honor, as are Mason County, Kentucky, Mason County, West Virginia and Mason County, Illinois.