A dynasty called Bhauma or Kar (also known as Bhaumakara) established its rule over the coastal belt of Odisha in the first, half of the eighth century A. D.. The capital of this dynasty, called as Guhadevapataka or Guhesvarapataka was situated near modern Jajpur town of the Jajpur district. The scholars have not been able to settle conclusively the origin and chronology of Bhaumas. K.C. Panigrahi has traced the origin of this dynasty on the basis of the Pasupati temple inscription of Nepal. According to this inscription, Rajyamati, the queen of the Nepalese king Jayadeva, was the daughter of Harsavarman who belonged to a royal family, called Bhagadatta and conquered Gauda, Odra, Kalinga and Kosala. Since the Bhaumas of Odisha claim their descent from Bhagadatta, Panigrahi concludes that Bhaumas of Odisha and Harsavarman, the ruler of Assam, belong to Bhagadatta. He presumes that Harsavarman, after his conquest of Odra i.e., the coastal belt of Odisha, installed a member of his family as the governor of the conquered territory, who subsequently proved to be the founder of the independent dynasty of Bhauma. Because of the chaotic political situation which prevailed in Bengal and Odisha during the early part of the eighth century, it is natural that such an invasion might have taken place. The linguistic similarity between Assamese and Oriya languages supports the possibility of interaction between the two regions in the early phase.
The scholars have also identified artistic affinity between Odisha and Assam. The Ganga images of Dah Parvatiya in the Tezpur district of Assam and of Ratnagiri in the Jajpur district possess similar iconographic features. The geographical location of Odisha is such that migration or invasion into its territory could have taken place from three directions – north-east, north-west and south-west. The Bhaumas had came from the north-east. Subsequently, the Somavamsis came from the north-west and the Gangas came from the south-west. Binayak Mishra and some other scholars hold that Odisha was the original home land of Bhaumas, and that they were a nonAryan tribe and most probably same as Bhuyans who reside in present day Odisha. Some scholars hold that Guhasiva, the Buddhist king of Kalinga, whose name has been mentioned in the Cylonese chronicle Dathavamsa might have been the founder of Bhauma rule in Odisha.
In Vishnu Purana there is the mention of a king, named Bhauma Guha who was ruling over Kalinga, Mahisya (Midnapore) and Mahendra. Some scholars presume that Bhauma Guha was the predecessor of the Bhaumas and that Guhadeva Pataka, the Bhauma capital, was named after him. The Bhaumas, in their inscriptions and copper plate grants, used a Samvat or era. According to K. C. Panigrahi, the initial year of the Bhauma era corresponds to 736 A.D. of the Gregorian calendar. Who was the founder of the “Bhauma dynasty? Who initiated this new era? The Bhauma records mention two ancestors of the Bhauma rulers of Orissa. They were Lakshmikaradeva and Kshemankaradeva. According to some, Kshemankaradeva initiated the new Bhauma era. According to others, the Bhaurna era begins with the accession of Kshemankaradeva’s son and successor, Sivakaradeva-1. Kshemankaradeva was a devout Buddhist.
Therefore, the Buddhist epithet ‘Paramopasaka’ has been applied to him in the Bhauma epigraphic records. After due analysis, Biswarup Das has accepted the view of S. N. Rajguru who fixes it in 736 A.D. and most of the scholars incline to accept this view.