Age of candidacy is the minimum age at which a person can legally hold certain elected government offices. In many cases, it also determines the age at which a person may be eligible to stand for an election or be granted ballot access.
The first known example of a law enforcing age of candidacy was the Lex Villia Annalis, a Roman law enacted in 180 BCE which set the minimum ages for senatorial magistrates.
^Broughton, Thomas; Marcia Patterson (1951). The Magistrates of the Roman Republic. American Philological Association. p. 388.