Re Pericles
Hi!
He held the position of STRATEGOS (general) for that period of time. Although the principle of rotation of office was involved in all elected/selected positions, the position of strategos (there were 10 strategoi annually elected from the 10 tribes)
could be re-elected and a successful and popular general could expect to serve several terms. Pericles, from an old, aristocratic family had prestige as well as success as an orator and commander and experienced what is believed to be an unprecedented length of tenure. Remember, too, that Strategoi were both civic and military leaders.
Check the sources for further elaboration:
*Burn, Periclean Democracy
*Forrest, The Emergence of Greek Democracy
*Bradley, Greek History
*Thucydides, The Peloponnesian War
etc, etc.
Hope this helps,
Magister