Kamrup, the modern district of Assam, takes its name from the great independent kingdom of Kamarupa. It is described in the Kalika Purana that immediately after Naraka of Mithila became the king of Assam and was placed in charge of the goddess Kamakhya; the name of the province was changed from pragjyotisa to Kamarupa.
The earliest epigraphic references to Kamarupa are how ever to be found in the well-known Allahabad in scrimption of Samudragupta, where Kamarupa is mentioned as frontier territory. In classical Sanskrit literature Pragjyotisa and Kama- rupa both occur side by side; for instance, in Kalidasa. In the story of Raghu's digvijaya as given in the Raghuvamsa the hero first came to Pragjyotisa and then to Kamarupa after having crossed the Lauhitya.
Author - H.V.Sreenivasa Murthy And B.K. Barua