In AD 224 Ardashir I, a Persian vassal-king, rebelled against the Parthians, defeated them in the Battle of Hormuz, and founded a new Persian dynasty, that of the Sassanids. He then conquered several minor neighboring kingdoms, invaded India, levying heavy tribute from the rulers of the Punjab, and conquered Armenia. The Sassanid Empire continued until 621 AD, when it was conquered and converted to a Caliphate by Arabia.
King Khusro II called the ‘victorious’, renewed traditional sassanian hostilities against the Byzantines. He won remarkable battles at Damascus in 613 AD and then at Jerusalem and Alexandria in 619 AD. The Byzantine armies fought back under the able leadership of Heraclius who successfully invaded Armenia and in 627 AD destroyed Khusro’s Palace at Dastagird. Khusro died while the empire was in revolt the following year.