quote:It was 11 years after the Declaration of Independence—and four years after American victory in the Revolutionary War—when a small group of delegates convened in Philadelphia to create a new charter for governing the young nation. The result was the longest lasting, most successful, most enviable, and most imitated constitution man has ever known. The United States Constitution has secured an unprecedented degree of human freedom, upholding the rule of law, securing the blessings of liberty, and providing the framework for the people of America to build a great, prosperous, and just nation unlike any other in the world.
...From May 25 to September 17, 1787, delegates from 12 states met in what is now Independence Hall at Philadelphia to “form a more perfect Union” and establish a government that would “secure the Blessings of Liberty to ourselves and our posterity."
...On the Convention’s last day, September 17, 1787, now celebrated as Constitution Day, Benjamin Franklin, the 81-year-old patriarch of the group, praised the Constitution as possibly the best ever written. He observed of the sun painted on the back of George Washington’s chair: Now, “I have the happiness to know that it is a rising and not a setting Sun.” The 39 delegates who remained through the four months, representing 12 states, signed the Constitution and sent it to the Congress of the Confederation, and the Convention officially adjourned."
Source, more: http://www.heritage.org/initiatives/first-principl es/primary-sources/the-constitution-of-the-us