In 1789, at Madison’s instigation, Congress sent 12 proposed amendments to the states for ratification. 10 of them became the Bill of Rights. One other was ratified in 1992: the 27th Amendment.
What happened was that in the late 1970s, a staffer at the Texas Capitol noticed that this proposed amendment was sitting there unratified. He then undertook, using his own money, to persuade state legislators around the country to pick it up and agree to it. His triumph came in 1992.