The oldest Sannyasa Upanishads have a strong Advaita Vedanta outlook, and these pre-date Adi Shankara. Most of the Sannyasa Upanishads present a Yoga and nondualism (Advaita) Vedanta philosophy. This may be, states Patrick Olivelle, because major Hindu monasteries ("matha") belonged to the Advaita Vedanta tradition. Almost all medieval Sannyasa Upanishads are also Advaita Vedantin because of these monasteries. The only significant exception is the 12th-century Shatyayaniya Upanishad, which presents qualified dualistic and Vaishnavism (Vishishtadvaita Vedanta) philosophy and is likely linked to a Vaishnavism monastery.