The term "
tetrarchy" (from the
Greek τετραρχία "leadership of four [people]") describes any form of government where power is divided among four individuals, but in modern usage usually refers to the system instituted by
Roman Emperor Diocletian in 293, marking the end of the
Crisis of the Third Century and the recovery of the
Roman Empire. This Tetrarchy lasted until c. 313, when internecine conflict eliminated most of the claimants to power, leaving
Constantine in the East and
Licinius in the West.
