Article VII required nine state ratifications before the U.S. Constitution took effect.
The Constitutional Convention sent the proposed Constitution to the states in 1787. Article VII specified that approval by conventions in nine states would be sufficient to establish the Constitution among the states ratifying it, rather than requiring unanimous approval from all thirteen.
New Hampshire became the ninth state to ratify on June 21, 1788. That vote placed the Constitution into effect, although several states had not yet approved it. Virginia ratified shortly afterward, and New York followed in July 1788.
The number nine is sometimes confused with thirteen because the original United States consisted of thirteen states. Rhode Island did not ratify until May 29, 1790, nearly two years after the Constitution had taken effect. Article VII therefore created a threshold lower than unanimity while allowing the new government to begin operating.