The site for Washington DC was inhabited by an Algonquian-speaking people known as the Nacotchtank when the first Europeans arrived in the 17th century. However, Native American people had largely relocated from the area by the early 18th century. Washington DC did not become the nation's capital until 1800. In his "Federalist No. 43", published January 23, 1788, James Madison argued that the new federal government would need authority over a national capital to provide for its own maintenance and safety. Five years earlier, in an event known as the Pennsylvania Mutiny of 1783, a mob of unpaid soldiers besieged the Congress while it was meeting in Philadelphia. The Pennsylvania government refused requests to forcibly disperse the protesters, which emphasized the need for the national government not to rely on any state for its own security. Article One, Section Eight of the United States Constitution therefore permits the establishment of a "District (not exceeding ten miles square) as may, by cession of particular states, and the acceptance of Congress, become the seat of the government of the United States." However, the Constitution does not specify a location for the capital. In what later became known as the Compromise of 1790, Madison, Alexander Hamilton, and Thomas Jefferson came to an agreement that the federal government would pay each state's remaining Revolutionary War debts in exchange for establishing the new national capital in the Southern United States. On July 16, 1790, Congress passed the Residence Act, which approved the creation of a national capital to be located on the Potomac River, the exact area to be selected by President George Washington. Formed from land donated by the states of Maryland and Virginia, the initial shape of the federal district was a square measuring 10 miles (16 km) on each side, totaling 100 square miles. Two preexisting settlements were included in the territory: the port of Georgetown, Maryland founded in 1751, and the city of Alexandria, Virginia, founded in 1749. During 1791-92, Andrew Ellicott and several assistants, including Benjamin Banneker, surveyed the borders of the federal district and placed boundary stones at every mile point. Many of the stones are still standing. A new "federal city" was then constructed on the north bank of the Potomac, to the east of the established settlement at Georgetown. On September 9, 1791, the three commissioners charged with overseeing the capital's construction named the city in honor of President Washington. The federal district was named Columbia, which was a poetic name for the United States in use at that time. Congress held its first session in Washington on November 17, 1800. Shortly after arriving in the new capital, Congress passed the Organic Act of 1801, which officially organized the District of Columbia and placed the entire territory under the exclusive control of the federal government. Further, the unincorporated area within the District was organized into two counties: the County of Washington to the east of the Potomac and the County of Alexandria to the west. After the passage of this Act, citizens located in the District were no longer considered residents of Maryland or Virginia, which therefore ended their representation in Congress. In the 1830s, the District's southern territory of Alexandria went into economic decline partly due to neglect by Congress. Alexandria was a major market in the American slave trade and residents feared that abolitionists in Congress would end slavery in the District, further depressing the economy. As a result, Alexandrians petitioned Virginia to take back the land it had donated to form the District; a process known as retrocession. The state legislature voted in February 1846 to accept the return of Alexandria and on July 9, 1846, Congress agreed to return all the territory that had been ceded by Virginia. Accordingly, the District's current area consists only of land donated by Maryland. read more