Coin of Hormizd I, issued in what is now Afghanistan, and derived from earlier Kushan designs.
Coin of the Indo-Sassanid kushanshaVarhran I (early 4th century). Obv: King Varhran I with characteristic Indus Valley head-dress. Rev: Iranian bull (and also at times a Zoroastrian fire altar.
The Indo-Sassanids, Kushano-Sassanids or Kushanshas (also Indo-Sassanians) were a branch of the Sassanid Persians who established their rule in the northwestern Indian subcontinent during the third and fourth centuries at the expense of the declining Kushans. They were in turn displaced in 410 by the invasions of the Huna people. They were able to re-establish some authority after the Sassanids destroyed the Hephthalites in 565, but their rule collapsed under Arab attacks in the mid 7th century.
The Sassanids, shortly after victory over the Parthians, extended their dominion into Bactria during the reign of Ardashir I around 230 CE, then further to the eastern parts of their empire in western Pakistan during the reign of his son Shapur I (240–270). Thus the Kushans lost their western territory (including Bactria and Gandhara) to the rule of Sassanid nobles named Kushanshahs or "Kings of the Kushans".
Around 325, Shapur II was directly in charge of the southern part of the territory, while in the north the Kushanshahs maintained their rule until the rise of the Kidarites.
The decline of the Kushans and their defeat by the Sassanids led to the rise of an indigenous Indian dynasty, the Guptas, in the 4th century. In 410, the Hephthalites or Indo-Hephthalites conquered Bactria and Gandhara, thus temporarily replacing the Indo-Sassanids.
Lands of the Kushanshas (Indo-Sassanian) and Kushano-Hepthalites in 565 AD
The Hephthalites dominated the area until they were defeated in 565 AD by an alliance between the Gokturks and Sassanids, and some Indo-Sassanid authority was re-established. The Kushano-Hephthalites were able to set up rival states in Kapisa, Bamiyan, and Kabul. The 2nd Indo-Sassanid period ended with the collapse of Sassanids to the Rashidun Caliphate in the mid 7th century. Sind remained independent until the Arab invasions of India in the early 8th century. The Kushano-Hephthalites or Turkshahis were replaced by the Shahi in the mid 8th century.
The prophet Mani (210–276), founder of Manichaeism, followed the Sassanids' expansion to the east, which exposed him to the thriving Buddhist culture of Gandhara. He is said to have visited Bamiyan, where several religious painting are attributed to him, and is believed to have lived and taught for some time. He is also related to have sailed to the Indus valley area of Pakistan in 240 or 241, and to have converted a Buddhist King, the Turan Shah of India.
On that occasion, various Buddhist influences seem to have permeated Manichaeism: "Buddhist influences were significant in the formation of Mani's religious thought. The transmigration of souls became a Manichaean belief, and the quadripartite structure of the Manichaean community, divided between male and female monks (the 'elect') and lay follower (the 'hearers') who supported them, appears to be based on that of the Buddhist sangha" (Richard Foltz, Religions of the Silk Road, New York: Palgrave Macmillan, 2010).
The Indo-Sassanids traded goods such as silverware and textiles depicting the Sassanid emperors engaged in hunting or administering justice. The example of Sassanid art was influential on Kushan art, and this influence remained active for several centuries in the northwest Indian subcontinent.