<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> The drafting of the Constitution of the United States began on May 25, 1787, when the Constitutional Convention met for the first time with a quorum at the Pennsylvania State House (now Independence Hall) in Philadelphia, Pennsylvania to revise the Articles of Confederation, and ended on September 17, 1787, the day the Constitution drafted by the convention's delegates to replace the Articles was adopted and signed . The ratification process for the Constitution began that day, and ended when the final state, Rhode Island, ratified it on May 29, 1790 . In addition to key events during the Constitutional Convention and afterward while the Constitution was before the states for their ratification, this timeline includes important events that occurred during the run - up to the convention and during the nation's transition from government under the Articles of Confederation to government under the Constitution, and concludes with the unique ratification vote of Vermont, which at the time was a sovereign state outside the Union . The time span covered is 5 years, 9 months, from March 25, 1785 to January 10, 1791 . </P> <P> March 25 Maryland--Virginia conference convenes </P>

When was the constitution of united states ratified