Kashyapa is the son of king Dathusena & Mugalan is the brother of him. According to the rules of those days, after the death of Dathusena the royalty should be belongs to Mugalan. But Kashyapa wants to get the royalty because he believed he is the one who suitable for the royalty than Mugalan. The reason for that is Kashyapa has won the war against to south Indians. After-wards he killed king Dathusena and got the royalty of Anuradhapura.
He recived the name as “Pithru Gathaka Kashyapa” and also people and monks were disgraced the Kashyapa. After the murder of Dathusena Mugalan attacked to Kashyapa. Because of that Kashyapa has moved to Sigiriya Rock from Anuradhapura for save his life from his brother’s attacks.
He selected the Sigiriya Rock as his Citadel and he was built his palace on top of the Sigiriya Rock with and amazing technology.