Vedic literature comprises Samhitas (collections, namely collections of hymns and Mantras), Brahmanas (voluminous prose texts, especially related to sacrificial rites and ceremonies), Aranyakas (forest texts, which contain chiefly the meditations of forest-hermits and deal with mysticism of sacrifices) and the Upanishads(secret doctrines partly included in other Vedic texts and partly reckoned as independent works) There are four Vedas: Rigveda, Yajurveda, Samveda and Atharvaveda. According to the Mahabhasya of Patanjali, there were 21 shakhas of Rigveda, 9 of Atharvaveda, 101 of Yajurveda (86 of Krishna Yajurveda and 15 of Shukla Yajurveda, according to later authorities) and a 1000 varieties of chanting of Samaveda. Nevertheless, although only thirteen or so Shakhas of the Vedas are extant now, we do possess names of most of the lost Shakhas of the Rigveda, Yajurveda and Atharvaveda.