Philadelphia hosted the Constitutional Convention that drafted the United States Constitution.
Delegates met at the Pennsylvania State House, now called Independence Hall, from May 25 to September 17, 1787. Although the gathering was initially called to revise the Articles of Confederation, the delegates ultimately proposed an entirely new system of government.
George Washington presided over the convention. Delegates debated representation, executive authority, federal powers, slavery, and the relationship between national and state governments. The resulting document was signed on September 17, 1787, and sent to the states for ratification.
Philadelphia was the largest city in the United States at the time and had already hosted major revolutionary-era events. It served as the national capital under the Confederation Congress before the federal government moved to New York City and later to Washington, D.C.