Since 1824.
The elected president and vice president
In 1823, after several generals revolted against a monarchy led by Agustin I and setup a federal presidential republic.
The president and the vice president runs the office together as a unit
No limit
Should this question be about the USA the following pieces of information can answer it. Democrat Woodrow Wilson has run for office two times and by custom set by George Washington does not run for a third term, The date is 1921, and a November 1920 US presidential election has Republican Warren Harding elected as US president. He serves from 1921 to 1923. From 1923 to 1929, Republican Calvin Coolige becomes the 30th US president and servers from 1923 to 1929. Republican Herbert Hoover is elected in 1928 and serves from 1928 to 1933. Thus for all practical purposes, the 1920's have had a Republican, 3 of them, serving as US President.
There was some consideration to make George Washington the king of America. However, Washington rejected the idea, believing in a republican form of government. He instead chose to become the first President of the United States.
(in the US) The President is elected NOT appointed.
1809 - James Madison becomes US President 1812 - war of 1812 includes british and US 1814 - the british set white house on fire 1815 - Napoleon is defeated at Waterloo 1816 - James Monroe is elected US President 1820 - Missouri Compromise balances # of free and slave US states 1821 - Peru and Mexico gain independence from Spain 1823 - Monroe doctrine issued 1824 - John Quincy Adams is elected US President 1825 - Erie Canal Completed / First public railroad operates in England 1828 - Andrew Jackson is elected US President 1831 - Nat Turner leads slave rebellion 1833 - Slavery is abolished by the British empire 1836 - Martin Van Buren is elected US President 1837 - Alexandrina Victoria becomes queen of Britain 1840 - William Henry Harrison is elected US President 1841 - John Tyler becomes US President when Harrison dies of pneumonia 1844 - James K. Polk is elected US President 1846 - war with Mexico begins 1848 - war ends with Mexico 1848 - Zachary Taylor is elected US President 1849 - California Gold rush begins
The South set up its own govenment and elected its own president, Jefferson Davis.
if a US President is elected for 2 terms he will serve 8 years unless he resigns, dies, or becomes unable to perform his duties. A vice-president (or other official) who succeeds an elected president may serve for up to 2 years without forfeiting eligibility to two elected terms. So a President can serve a maximum of 10 years under the law set forth in the 22nd Amendment.
The 22nd Amendment set term limits for the president. The amendment was prompted by the fact that President Roosevelt had been elected to four terms and could have been elected to more had he not died in office. Some felt President Washington had set the number of terms that were intended by the founding fathers when he declined to run for a third term.
Kings are determined by heredity and serve for life or until they resign. President are elected and serve for term of fixed length as set by a Constitution.