Nanyadeva (IAST: Nānyadev^[1]) was the founder^[2][3] of the Karnat dynasty of Mithila.^[4] He established his capital in Simraungadh and ruled the greater Mithila region for 50 years.^[5][6] He is known for his generosity, courage, and patronage of scholars.^[7] He was from Karnat Kshatriya Kula and began to rule Mithila from the citadel of Simraungadh which was situated on the modern India-Nepal border, in 1097 CE. The stone inscription found at Simraongarh and Nepālavaṃśāvalī^[8] clearly states that he made an erection in a Singha Lagna of a Saturday in a Sravana, the tithi being Sukla seven and the Naksatara Svati in the year 1019 Shaka (July 10, 1097 AD).^[9]

Nanya is a word of Karnatic origin and Sanskritised form of Nanniya.^[10] Nanyadeva means "the dearest of god" (Nanya means "dearest" and deva means "god").^[11] The Andhratharhi inscription of his minister, Shridhardas refers Nanyadeva as Mahasamantadhipati, Dharmamavaloka and Sriman Nanyapati.^[12]

Little is known about Nanyadeva's early life although it is believed that Nanyadeva arrived in Mithila as part of the Chalukaya invasions of the North during the second half of the 11th century. The Chalukyas would likely have been accompanied by many military adventurers who carved out small principalities of their own in North Bihar and Nanyadeva would have been among them.^[12] Inscriptions from the Sena dynasty refer to Nanyadeva as "Karnata-Kulabhusana" indicating an origin from the area around modern-day Karnataka in India. His original stronghold in Mithila was Nanapura in Champaran district of Bihar however he later shifted his capital to Simraungadh which would remain as the main capital until the end of the Karnat dynasty.^[5]

In Vidyapati's Purush Pariksa, Nanyadeva is confirmed to have gained control of Mithila by 1097 CE. Nanyadeva was a contemporary of Ramapala of the Pala Empire with whom he had fallen into conflict and then subsequently gained independence for Mithila.^[12] Following on from the Varendra rebellion, the Pala Empire was in a state of disintegration with the Sena dynasty establishing a power base in the Radha region. Both the Karnatas and the Senas coveted the Pala territories of Gauda and Vanga and a conflict began between Mithila and the Senas with the Senas coming out victorious as per the Deopara inscription. Following on from this conflict, local tradition in Mithila confirms that parts of Mithila came under Sena hegemony however these were later regained by Nanyadeva's heir and son, Gangadeva.^[12]

To compensate for these losses, Nepalese traditions assert that Nanyadeva launched attacks into the Kathmandu Valley of Nepal which at the time was under the Thakuri dynasty.^[12] He may have extended his territory into parts of Nepal although the overall goal seems to have been to capture loot rather than land. The territories west of Nanyadeva's Kingdom were ruled by the Gahadavalas and Nanyadeva maintained peaceful relations with them and even sent his son, Prince Malladeva to serve in the army of the Gahadavalas.^[12]

Many modern scholars, as well as the people of the region, view Nanyadeva as a "son of Mithila" who liberated the region following the fall of the Videhan monarchy. The Karnata rule is not viewed as foreign as they established their power in Mithila itself, unlike others who ruled from outside.^[13] he was succeeded by two sons, Gangadeva and Malladeva.^[14]

After the fall of the Karnat dynasty in 1324 and the power vacuum that followed, the Maithil Brahmins with the patronage and protection of the Tughlaqs came to power and formed the Oiniwar dynasty. The Karnats mainly split into two branches with Nanyadeva's descendant, Harisimhadeva fleeing to Nepal and marrying into the reigning Malla dynasty.^[5]

Evidence also exists of Karnat descendants still maintaining control in parts of Mithila. In Champaran, the ruler was Prithvisimhadeva and his successors including Madansimhadeva. Their territory extended up to Gorakhpur district. Prithvisimhadeva was considered to be a descendant of Harisimhadeva. Other remnants of the Karnat dynasty were also found in Saharsa and Madhepura districts, where inscriptions have been found that refer to a ruler called Sarvasimhadeva.^[20]