U.S. Constitution
The U.S. Constitution was signed on September 17, 1787 at the Constitutional Convention in Philadelphia. The document stands as the highest law of our nation and lays out America’s basic government structure. Delegates came from all 13 colonies to discuss and debate the contents on the Constitution. The Founding Fathers realized that the previous ruling document, the Articles of Confederation, was too weak and that a new document needed to be drafted. The Constitution established a strong central government for the nation, but some feared this would not give enough freedom to individuals. As a result, ten amendments called the Bill of Rights that secured individual freedoms were added to the Constitution after it was signed.
“We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.”—Preamble of the U.S. Constitution
“The proposed Constitution, so far from implying an abolition of the State governments, makes them constituent parts of the national sovereignty, by allowing them a direct representation in the Senate, and leaves in their possession certain exclusive and very important portions of sovereign power.”—Federalist Paper 9
The Constitution established the Judicial, Legislative, Executive branches of government, and a system of checks and balances to keep any one branch from becoming too powerful.
Benjamin Franklin was the oldest delegate to sign the Constitution, at 81 years old. 
The Constitution was signed on 1787, but was not ratified until 1788.