Jagadguru (Sanskrit: जगद्गुरु), literally meaning the Guru of the world, is a title used in Sanātana Dharma. Traditionally, it has been bestowed upon or used for Ācāryas belonging to the Vedānta school (among the six traditional schools of thought in Hinduism) who have written Sanskrit commentaries on the Prasthānatrayī (literally the three sources) - the Brahma sūtras (the original scripture of Vedānta), the Bhagavad-gītā (part of the Mahābhārata) and the principal Upaniṣads. Historically, Jagadgurus have established a lineage (Paramparā), established an institution to spread Dharma, who have been based in Varanasi, famous for being the centre of Sanskrit study and the "Capital of All Knowledge".