Complex sentence: For centuries the European colonial occupiers the Portuguese, the Dutch and the British occupied by violent force and ruled the countryside in Batticaloa which was nominally part of the Kandyan kingdom but were administered by local Vannimai chiefs.
Split into simpler sentences: For centuries the European colonial occupiers the Portuguese, the Dutch and the British occupied by violent force and ruled the countryside in Batticaloa. Prior to the colonial occupation Batticaloa and the surrounding are was nominally part of the native Kandyan kingdom but were administered by local Vannimai chiefs.