The U.S. Constitution was written under the authority of the Constitutional Convention, which was made up of 55 delegates from 12 of the 13 original colonies. After it was written, it had to be ratified by at least nine of the states, which occurred on July 21, 1788.
The final document was finalized by Alexander Hamilton, James Madison, William Samuel Johnson, Rufus King and Gouverneur Morris. Benjamin Franklin, who was a member of the Second Continental Congress, which signed the Declaration of Independence, was part of the Constitutional Convention. To assist in getting the public to support the new document, Madison and Hamilton wrote 85 essays, called the Federalist Papers, urging ratification.