The zero year of Saka era (also Shalivahana era, Sakabda) began in 78 A.D.
Kanishka succeeded to the throne of Kushan Empire in 78 A.D.
The Christian year 78 A.D. has been accepted by most historians as the year of the foundation of the Saka Era. For centuries thereafter and till now, this era has continued to dominate the Indian reckoning of the years and time.
It appears paradoxical that though Kanishka was a Kushana Emperor, and not a Saka. Yet the era founded by him became famous as the Saka Era.
This was probably for the fact that to the Indian people of that time the Sakas and the Kushanas appeared as the same type of external tribes to pass under a common name as Saka. Since the Sakas came and settled earlier, and also became Indianized before the Kushans, their name became more familiar to the Indians. Thus that the Kushanas also passed under that name among the common people, and therefore, the era of Kanishka became famous as the Saka Era.