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.
Second-term curse
According to the "curse", the second terms of U.S. presidents have usually been plagued by a major scandal, policy inertia, some sort of catastrophe, or other problems. There have been twenty-one U.S. presidents who have served a second term, each of whom has faced difficulties attributable to the curse. The legend behind the second-term curse is that after Franklin D. Roosevelt broke the "de facto" second term limit by running for third and fourth terms, the ghost of George Washington might have put a curse on any president who seeks a second term. This legend notwithstanding, several presidents who served prior to Roosevelt, including Washington himself, allegedly succumbed to the curse.