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.
Federalist No. 72
The twenty-second Amendment to the Constitution imposed the present two-tier term limit on the executive branch. Today, U.S. presidents can only serve two terms, or if a succession has taken place, ten years, as president of the country.