Which constitutional amendment was enacted in 1951 to limit the number of terms of the US President?

Interestingly, for the most part of US history, the constitution did not limit the number of times a person can be elected to the highest office of the land. George Washington, the first US president, did not seek reelection after his second term expired. This custom was followed by subsequent Presidents, including Thomas Jefferson, for a long time.

That all changed when Franklin D. Roosevelt strayed from the custom by running for office and winning a third and fourth term. Seeing the danger of unlimited presidential terms, Congress passed the 22nd Amendment on March 21, 1947, which was ratified by 3-4th of the states by February 27, 1951.