Here is what happened.  Due to the failure of the Articles of Confederation a Constitutional Convention convened in Annapolis, MD in 1786 and then reconvened in Philadelphia, PA in 1787.  The Constitution was vehemently argued over from May - September 1787 and the compromise document was submitted to the People and their elected representatives in each State for ratification.  The ratification process was no slam dunk for the supporters of the Constitution, it almost failed.  Supporters of the Constitution were known as Federalists, non-supporters as Anti-Federalists.  Thanks to the anti-Federalists we had the first 10 amendments to the Constitution known as the Bill of Rights in 1791.  But, those first amendments actually started out as 12.  One of those 12 became part of the Constitution on 5 May 1992, as the 27th Amendment and believe it or not, one amendment is still pending before the states.