On May 14, 1787, delegates to the Constitutional Convention begin to assemble in Philadelphia to confront a daunting task: the peaceful overthrow of the new American government as defined by the Article of Confederation. Although the convention was originally supposed to begin on May 14, James Madison reported that a small number only had assembled. Meetings had to be pushed back until May 25, when a sufficient quorum of the participating states—Massachusetts, New York, New Jersey, Pennsylvania, Delaware, Virginia, North Carolina, South Carolina and Georgia—had arrived.

Four years after the United States won its independence from Great Britain, 55 state delegates, including George Washington, James Madison and Benjamin Franklin, convene in Philadelphia to compose a new U.S. constitution on May 25, 1787.

On July 13, 1787, Congress enacts the Northwest Ordinance, structuring settlement of the Northwest Territory and creating a policy for the addition of new states to the nation. The members of Congress knew that if their new confederation were to survive intact, it had to resolve the states’ competing claims to western territory.

In Philadelphia, delegates to the Constitutional Convention begin debating the first complete draft of the proposed Constitution of the United States.

The Constitution of the United States of America is signed by 39 delegates present at the conclusion of the Constitutional Convention in Philadelphia. Supporters of the document waged a hard-won battle to win ratification by the necessary nine out of 13 U.S. states.

In Dover, Delaware, the U.S. Constitution is unanimously ratified by all 30 delegates to the Delaware Constitutional Convention, making Delaware the first state of the modern United States.

On December 12, 1787, Pennsylvania becomes the second state to ratify the Constitution, by a vote of 46 to 23. Pennsylvania was the first large state to ratify, as well as the first state to endure a serious Anti-Federalist challenge to ratification.