Philadelphia hosted both the 1776 Declaration debate and the 1787 Constitutional Convention.
The Second Continental Congress met in Philadelphia when it adopted the Declaration of Independence. The meeting took place in the Pennsylvania State House, now called Independence Hall. Eleven years later, delegates returned to the same building for the Constitutional Convention.
The 1787 convention originally gathered to revise the Articles of Confederation, but delegates instead designed an entirely new constitutional system. George Washington presided, and the final document was signed on September 17, 1787.
Philadelphia served as the United States capital under the Confederation and again from 1790 to 1800. New York City was the first capital under the Constitution, while Washington, D.C., became the permanent capital in 1800. Philadelphia's concentration of printers, merchants, and political institutions made it a major center of the founding era.