Be this as it may, the Virginia Assembly ceded to the federal government on December 3, 1789, a generous slice of Fairfax County to be incorporated with the State of Maryland's larger portion into a district for the federal capital, ten miles square. The Congress of the United States was pleased to accept this, and later an additional act of Congress of March 3, 1791, amended and repealed a part of the first act, naming Alexandria part of the ceded territory. And so for the next fifty-six years we have no longer Alexandria in Virginia, but Alexandria in the District of Columbia. The Federal City (afterward Washington) which did not officially become the nation's capital until 1800, was an undrained marsh in 1790. Travelers visiting Alexandria about that time described it as having "upwards of three hundred houses," many "handsomely built."[49] In 1795 Thomas Twining passed through Alexandria and commented: "What struck me most was the vast number of houses which I saw building ... the hammer and the trowel were at work everywhere, a cheering sight."[50] The Duc de la Rochefoucauld in the following year stated: "Alexandria is beyond all comparison the handsomest town in Virginia and indeed is among the finest in the United States."[51] That same year, 1796, Isaac Weld remarked, "Alexandria is one of the neatest towns in the United States. The houses are mostly of brick."[52] Virginians were largely their own architects. Thomas Jefferson designed Monticello, the University of Virginia, and the Capitol at Richmond; George Mason built Gunston Hall; and George Washington directed the transformation of Mount Vernon from a simple villa into the famous mansion it is. Alexandria "Undertakers," or contractors, did the work--James Patterson in 1758 and Going Lamphire from 1773 onward for a number of years. One Mr. Sanders, was called in about roof troubles and afterwards dismissed. John Carlyle was the great gentleman architect and builder of Alexandria. He built his own fine house, he took over Christ Church in 1773 when James Parsons failed to complete his contract, and he also superintended the erection of the Presbyterian meetinghouse. James Wren, Gentleman, is remembered as the designer of Christ Church in 1767. Thomas Fleming is referred to as a ship's carpenter and "one who is inclined to serve the Town." A story goes that George Coryell built a gate in Philadelphia which so pleased the first President that he persuaded him to move to Alexandria. True or not, the local _Gazette_ carried Coryell's advertisements of building materials and he is known to have built a number of houses. Robert Brockett was building in 1785 the Presbyterian Manse. Benjamin Hallowell, William Fowle, and William Yeaton at a later time proved themselves able architects.