Babak was the ruler of a small town called Kheir. Babak's efforts in gaining local power at the time escaped the attention of
Artabanus IV, the
Arsacid Emperor of the time. Babak and his eldest son Shapur managed to expand their power over all of Persis. The subsequent events are unclear, due to the sketchy nature of the sources. It is however certain that following the death of Babak around 220,
Ardashir who at the time was the governor of Darabgird, got involved in a power struggle of his own with his elder brother
Shapur. The sources tell us that in 222, Shapur was killed when the roof of a building collapsed on him. Ardaxšir (Artaxerxes) V, defeated the last legitimate Parthian king,
Artabanos V in AD 224, and was crowned at
Ctesiphon as
Ardaxšir I (Ardashir I),
šāhanšāh ī Ērān, becoming the first king of the new
Sasanian Empire. At this point, Ardashir moved his capital further to the south of Persis and founded a capital at Ardashir-Khwarrah (formerly Gur, modern day
Firouzabad). After establishing his rule over Persis,
Ardashir I rapidly extended the territory of his
Sassanid Persian Empire, demanding fealty from the local princes of Fars, and gaining control over the neighboring provinces of Kerman, Isfahan, Susiana, and Mesene. in
Sarvestan Artabanus marched a second time against Ardashir I in 224. Their armies clashed at
Hormizdegan, where
Artabanus IV was killed. Ardashir was crowned in 226 at
Ctesiphon as the sole ruler of Persia, bringing the 400-year-old
Parthian Empire to an end, and starting the virtually equally long rule of the
Sassanian Empire, over an even larger territory, once again making Persia a leading power in the known world, only this time along with its arch-rival and successor to Persia's earlier opponents (the
Roman Republic and the
Roman Empire); the
Byzantine Empire. The Sassanids ruled for 425 years, until the Muslim armies conquered the empire. Afterward, the Persians started to convert to
Islam, this making it much easier for the new Muslim empire to continue the expansion of Islam. Persis then passed hand to hand through numerous dynasties, leaving behind numerous historical and ancient monuments; each of which has its own values as a world heritage, reflecting the history of the province,
Iran, and
West Asia. The ruins of
Bishapur,
Persepolis, and
Firouzabad are all reminders of this. Arab invaders brought about a decline of Zoroastrian rule and made Islam ascendant from the 7th century. ==See also==