In tantric Hinduism and Vajrayana Buddhism, a “siddha” is one who has mastered “siddhis,” or the magical powers that come with yogic practice. The “Great Siddhas” (mahasiddhas) were a semi-mythical group of tantric masters, men and women, who lived in medieval India. They were known for their extraordinary meditative powers, religious poetry, and their transgressive lifestyles, including dwelling in charnel grounds, drinking alcohol, fighting, and having sex. Many Himalayan Vajrayana traditions trace their initiation lineages back to the Mahasiddhas. Depictions of sets of eight, eighty-one, or eighty-four Mahasiddhas are a popular subject in Himalayan art.