"We may legitimately conclude: "Th ere were a number of Saka Eras. Two of them were much older than that of 78 A.D ., and one of them which both Bhattotpala and Varahamihira have used to indicate the epochs of their works went back to the middle of the 6th century before Christ: the year 551-550."
January 1, 1970
https://en.wikiquote.org/wiki/K._D._Sethna