Āryadeva (fl. 3rd century CE) (Tibetan འཕགས་པ་ལྷ་, 'Phags-pa-lha), was a disciple of Nagarjuna and author of several important Mahayana Madhyamaka Buddhist texts. He is also known as Kanadeva, recognized as the 15th patriarch in Chan Buddhism, and as "Bodhisattva Deva" in Sri Lanka.
According to one source, Aryadeva was born as the son of a Sinhalese king. A biography that was translated by Kumarajiva into Chinese states that Aryadeva was born into a South Indian Brahmin family. He is considered the co-founder of Mahayana philosophy. Aryadeva was a student of Nagarjuna and contributed significantly to the Madhyamaka school. According to the Drikung Kagyu school of Tibetan Buddhism, Garchen Rinpoche is the current incarnation of Aryadeva.
Most of Aryadeva's works were not preserved in the original Sanskrit but mainly in Tibetan and Chinese translations. His best-known text is probably the Catusataka (400 verses), in sixteen chapters of twenty-five stanzas each. Several important works of esoteric Buddhism (most notably the Caryamelapakapradipa or "Lamp that Integrates the Practices") are attributed to Aryadeva. Contemporary research suggests that these works are datable to a significantly later period in Buddhist history (late ninth or early tenth century), but the tradition of which they are a part maintains that they are (at least in some measure) the work of the Madhyamaka Aryadeva. Traditional historians (for example, the 17th century Tibetan Tāranātha), aware of the chronological difficulties involved, account for the anachronism via a variety of theories, such as the propagation of later writings via mystical revelation. A useful summary of this tradition, its literature, and historiography may be found in Wedemeyer 2007.