Pax RomanaPax Romana - After a half-century of civil and foreign wars, and the transition from republic to empire, Rome entered a period of relative internal peace which lasted for approximately two centuries; from the Battle of Actium in 31 B.C., until the death of Emperor Marcus Aurelius in 180 A.D.. There was, however, a one-year interruption between 68 and 69, after the suicide of Nero, in which the empire fell into civil war and the Julio-Claudian line was replaced by the Flavian dynasty; the so-called "Year of the Four Emperors". After 180, Rome began its slow decline, and eventually barbarian invasions that would end the Western Empire for good.