In the early Roman Republic, when things were still clinging to some approximation of the law, they were limited to a 1-year term to be shared with another consul, and then not allowed an immediate repeat term (they had to wait a number of years). In fact, across the ancient world in republics, very short term limits seem to be the norm. Of course, some people held office for longer, but often this was a problem or abuse, not the intended functioning.
By comparison, although I vaguely remember some agitation for shorter terms, America opted for four years. Why such a long period of time? Or was the roman system just exceptionally short?
If you want, you can tackle the question either from the perspective of America (why are American terms so long) or Rome (why are Roman terms so short). Each can help explain the other.
MY BS IN AMERICAN POLITICAL PHILOSOPHY IS FINALLY USEFUL. Someone wilth more qualifications than me can probably go through the debates and found out why they changed their minds.
It was debated heavily during the Constitutional Conventions of 1787.
The Virginia Plan, introduced by Edmund Randolph on May 29, called for the creation of a National Executive elected by the Congress. On the initial consideration of the proposal, the delegates on June 1, June 2, and June 4 agreed on a single executive who would serve a seven year term and be ineligible for re-election. On June 18, Hamilton surprised the delegates with a proposal for a President for life. On July 26, the delegates approved a seven-year term for the President. But he would be ineligible for re-election!
On September 6 and 7, the delegates agreed to a four-year renewable term for the President and that he be a natural born citizen.