||Sasanka is often attributed with creating the first separate political entity in a unified Bengal called Gauda. He reigned in 7th century C.E, and some historians place his rule approximately between C.600 C.E and 636/7 C.E. His capital was called Karnasuvarna or Kansona and is located in modern Mursidabad. The development of the Bengali Calendar is also often attributed to Sasanka, as the starting date falls squarely within his reign period. Prior to his reign, Bengal was divided into three regions viz., Banga, Samatata and Gauda and was ruled by a feeble ruler Mahasenagupta belonging to the later Gupta (?) dynasty. Sasanka was one of his chieftains who rose to power taking the advantage of the weak ruler. After the death of Mahasengupta, Sasanka drove the later Guptas and other prominent nobles out of the ground to establish his own kingdom Gauda with the capital at Karnasuvarna.
The Egra copper plate inscription with a seal probably enumerates an account of a land grant at the time of Sasanka. It contains 20 lines on the obverse and 17 lines on the reverse. The copper plate datable to C.7th century C.E. is supposed to have been recovered from Egra, East Medinipur of West Bengal. It has been purchased by the Indian Museum in the year 1983 from a person hailing from the locality of Egra, East Medinipur, West Bengal.