Ancient Jaina scholars developed their own theories on Dhyana like other Indian religions, but little detail is mentioned in Jaina texts, and the Dhyana practices varied by sects within the Jaina tradition. Broadly, Jainism texts identify four types of meditation based on the nature of object. "Arta-dhyana", states Jaina meditation literature, occurs when one's focus is on anguish and unpleasant things. "Raudra-dhyana" occurs when the focus is on anger or perverse ideas or objects. "Dharmya-dhyana" focuses on religious ideas or virtuous objects, while "Shukla-dhyana" is the focus on pure ideas or bright objects. This classification of four Dhyana types may have roots, suggests Paul Dundas, in the earlier Hindu texts related to Kashmir Shaivism.