Pure Land Buddhist thought was further developed by a Tendai monk named Genshin (源信, 942-1017) who was a disciple of Ryōgen, the 18th chief abbot or zasu (座主) of Mount Hiei. Genshin wrote an influential treatise called , which vividly contrasted the Sukhavati Pure Land of Amitābha with the descriptions of the hell realms in Buddhism. Further, Genshin promoted the popular notion of the Latter Age of the Dharma, which posited that society had degenerated to a point when they could no longer rely on traditional Buddhist practices, and would instead need to rely solely on Amitābha's grace to escape saṃsāra. Genshin drew upon past Chinese Pure Land teachers such as Daochuo and Shandao.