The succession of Central Asian and West Asian peoples who entered north-western India through the Hindu Kush passes after the Mauryan decline, in the order Indo-Greeks, Shakas, Parthians (Pahlavas) and Kushanas.
- The usual sequence is Indo-Greeks (Bactrian Greeks) first, then the Shakas (Scythians), then the Parthians (Pahlavas), then the Kushanas (Yuezhi).
- Shakas (Scythians): the Western Kshatrapas ruled western India; Rudradaman I (2nd century CE) issued the Junagadh rock inscription (in chaste Sanskrit) recording repair of the Sudarshana lake.
- The Shaka era (starting 78 CE) is India's national calendar era, conventionally linked with the Kushana ruler Kanishka rather than a Shaka king despite its name.
- Parthians (Pahlavas): a short-lived power; King Gondophernes is associated with the tradition of St Thomas reaching India.
- Kushanas: the Yuezhi who built a large empire under Kanishka, patron of the fourth Buddhist council, Mahayana Buddhism and the Gandhara and Mathura art schools.
- Vikrama era (starting 58 BCE) is traditionally linked to a victory over the Shakas by a king Vikramaditya.
The invasion sequence, Rudradaman's Junagadh Sanskrit inscription and the Sudarshana lake, the Shaka era of 78 CE (national calendar) and the Vikrama era of 58 BCE are commonly tested facts.
The Shaka era (78 CE), India's official calendar, is conventionally credited to the Kushana Kanishka, not to a Shaka ruler; the Vikrama era (58 BCE) is the earlier one, so the two eras and their dates are often swapped.
Order of invaders: Indo-Greeks, Shakas (Rudradaman, Junagadh), Parthians, Kushanas (Kanishka); Shaka era 78 CE, Vikrama era 58 BCE.