Haṭh yoga is a branch of yoga. The Sanskrit word हठ Haṭh literally means "force" and thus alludes to a system of physical techniques. In India, Haṭh yoga is associated in popular tradition with the 'Yogis' of the Natha Sampradaya through its traditional founder Matsyendranath. Almost all hathayogic texts belong to the Nath siddhas, and the important ones are credited to Matsyendranath's disciple, Gorakhnath or Gorakshanath. Matsyendranath, also known as Minanath or Minapa in Tibet, is celebrated as a saint in both Hindu and Buddhist tantric and Haṭh yoga schools. However, James Mallinson associates Haṭh yoga with the Dashanami Sampradaya and the mystical figure of Dattatreya.According to the Dattatreya Yoga Sastra, there are two forms of Haṭh yoga: one practiced by Yajnavalkya consisting of the eight limbs of ashtanga yoga and another practiced by Kapila consisting of eight mudras. Currently, the oldest dated text to describe Haṭh yoga, the 11th-century CE Amṛtasiddhi, comes from a tantric Buddhist milieu.The oldest texts to use the terminology of hatha are also Vajrayana Buddhist. Later Haṭh yoga texts adopt the practices of Haṭh yoga mudras into a Saiva system, melding it with Layayoga methods which focus on the raising of kuṇḍalini through energy channels and chakras. In the 20th century, a development of Haṭh yoga, focusing particularly on asanas (the physical postures), became popular throughout the world as a form of physical exercise. This modern form of yoga is now widely known simply as "yoga".