A term limit is a legal restriction that limits the number of terms an officeholder may serve in a particular elected office. When term limits are found in presidential and semi-presidential systems they act as a method to curb the potential for monopoly, where a leader effectively becomes "president for life". This is intended to protect a democracy from becoming a de facto dictatorship. Sometimes, there is an absolute limit on the number of terms an officeholder can serve, while, in other cases, the restrictions are merely on the number of consecutive terms.
Term limits have a long history. Ancient Greece and Ancient Rome, two early classic republics, had term limits imposed on their elected offices as did the city-state of Venice.
In ancient Athenian democracy, only offices selected by sortition were subject to term limits (one term of one year for each office, except members of the council of 500 (boule), where it was possible to serve two one-year terms, non-consecutively). Elected offices were all subject to possible re-election, although they were minoritarian, these positions were more prestigious and those requiring the most experience, such as military generals and the superintendent of springs.
In the Roman Republic, a law was passed imposing a limit of a single term on the office of censor. The annual magistrates—tribune of the plebs, aedile, quaestor, praetor, and consul—were forbidden reelection until a number of years had passed. (see cursus honorum, Constitution of the Roman Republic). Also there was a term limit of 6 months for a dictator.