Kundalini yoga in the Natha Sampradaya and Vajrayana in Tibetan Buddhism both take their origin from the Mahasiddhas who were active in India from the 8th century to the 12th century. Kundalini yoga practices formed the core of the teachings of a number of these Mahasiddhas and are strongly represented in both Tibetan Buddhist practices and contemporary kundalini yoga practices. Kundalini yoga was spoken of as "Candali yoga" by these Mahasiddhas and became known as gTummo rnal 'byor in Tibet. Candali yoga was a key practice of the famous Tibetan yogin Milarepa.