As the most important canonical treatise on Buddha-nature, the Ratnagotravibhaga (also known as Uttaratantrasastra, Tib. rgyud bla ma) established the doctrinal foundations for the Mahayana philosophy of tathagatagarbha, the doctrine according to which all sentient beings are either inherently buddhas or endowed with the potential for awakening. Among the most prominent Tibetan commentaries on this text figures that of the Sakya master Rongton Sheja Kunrig, a prolific writer who was active during the golden age of Tibetan Buddhist philosophy. Refuting on one hand the notion that Buddha-nature is synonymous with mere emptiness, and on the other that the mind is inherently endowed with the Buddha qualities, Rongton argues for an understanding of Buddha-nature that embraces both aspects of the nature of mind: cognizance and emptiness.