George Washington
At the end of his second term, Washington retired for personal and political reasons, fatigued and disgusted with personal attacks, and to assure a truly contested presidential election could be held. He did not feel bound to a two-term limit, but his retirement ultimately set precedent. The two-term limit to the presidency was formalized with the 1951 adoption of the Twenty-second Amendment to the United States Constitution. Washington is often credited with setting the principal of a two-term presidency, but it was Thomas Jefferson who first refused to run for a third term on political grounds.
Twentieth Amendment to the United States Constitution
In September 1788, after the necessary nine states had ratified the Constitution, the Congress of the Confederation set March 4, 1789, as the date "for commencing proceedings" of the newly reorganized government. Despite the fact that the new Congress and presidential administration did not begin operation until April, March 4 was deemed to be the beginning of the newly elected officials' terms of office, and thus of the terms of their successors. The Constitution did not specify a date for federal elections, but by the time of the second presidential election in 1792, Congress had passed a law requiring presidential electors to be chosen during November or early December. By 1845, this was narrowed to a single day, in early November. Congressional elections were generally held on the same day.