Nothing is definitely known about Sasanka’s early life. Possibly he was a feudatory under the Gupta emperor. Later, taking advantage of the decline of the Gupta Empire he began to rule over Gauda independently. Sasanka established his capital at Karnasuvarna near Berhampore in the district of Murshidabad.
Sasanka, a brave warrior, included different territories of Bengal into the kingdom of Gauda, but this could not satisfy his lust for conquest of kingdoms. He then conquered Magadha, Utkal, Kangod in the district of Ganjam, etc.
He entered into a long drawn warfare with Harshavardhana of Kanauj, who, however, could not do any harm to the kingdom of Gauda during Sasanka’s lifetime.