The Kingdom of Kamata was between the 11-12th Century A.D. by the dynasties of Pala & Sena. Then after by the Khen dynasty in the 14th century AD until 1498 AD. Then the King Nilambar was defeated by the Sultan Hussein Shah of Gaud, who had it ruled by the Koch dynasty from early on in the 16th Century.
When the English came along they Anglicized the term Koch to Cooch, hence the name Cooch Behar State.
Dr.Buchanan Hamilton in 1808 had left a vivid description along with a sketch of the mound and site which still hold good in authenticity. According to Dr. R.D. Banerjee stodd as buffer kingdom between Ohoms of Assam and Muslim Kingdom of Bengal in the 15th century AD. He opined that the khens might built Gosanimari, but it is also possible that these Mongoloid people only used the ruins of fortification which had been built several centuries before. After the independence Archaeological Survey of India took over the responsibility of this site.
Findings It is believed parts of the ancient kingdoms important temples and buildings are now buried under a large grass grown mound. So far two large stone wells have been excavated, along with a large stone walls and a number of idols too. Pottery work includes vases, bowls, basin, dish, beaker etc. The facial and physiognomical delineation indicate the idols are the products of c. 11th and 12th century AD and influenced by Pala-Sena school of art.
Goshanimari's Rajpat situated in 13kms. from Dinhata town. Goshanimari's history is very important for medieval period in East and North-east India. Goshanimari (Kamtapur) is capital of the Kamtapur State in medieval period (1228AD to 1510AD). Kamtapur State established by Maharaja Sandha Roy the year of 1228AD.Maharaja Sandha Roy's father was last king of Kamrup State, Maharaja Pithu Roy.Maharaja Sandha Roy change the name of Ancient Kamrup State, new name is 'Kamtapur State” and change his capital, new capital is 'Kamtapur', present name is 'Goshanimari'. “Kamta Originally denoted the western part of Brahamputra Vally to Koshi River and it was included within the Ancient Kingdom of Kamrupa”. The Mound of Rajpat Maharaja Nilambar Khen was defited by Hushen Saha. So, some year “Kamtapur State” was Afgan Colony the year of 1498/99AD to 1501AD. The last King of “Kamtapur State” wasMaharaja Durlovendra the year of 1510AD. After words the name of “Kamtapur State” is known as “Cooch-Behar State”.