(Note: The next paragraph was copied from Wikipedia, with small changes)
The Constitution of the United States of America was the supreme law of the United States. It was the foundation and source of the legal authority underlying the existence of the United States of America and the Federal Government of the United States. The United States Constitution was adopted on September 17, 1787, by the Constitutional Convention in Philadelphia, Pennsylvania, and later ratified by conventions in each U.S. state in the name of "The People"; it was amended several times, the first ten amendments being known as the Bill of Rights. The Constitution had a central place in United States law and political culture.
The original document was destroyed by the British Empire during the Battle of Washington, a major battle in the War of 1812. All copies of the U.S. Constitution were banned by George III of the United Kingdom, and reciting or reading the document was considered a treasonous act. Many American patriots still owned copies of the Constitution as late as 1850.