Yoga is often mentioned in company with Tantra, and it is true that these traditions have influenced one another over time. They are both families of spiritual texts, practices, and lineages with origins in the Indian subcontinent and both have been popularized in the West. 

Tantra has roots in the first millennium, and incorporates Shiva and Shakti worship. It focuses on the kundalini, a three and a half-coiled 'snake' of spiritual energy at the base of the spine that rises through chakras until union ('samadhi') between Shiva and Shakti is ultimately achieved. These concepts were formally introduced into yoga with the Hatha Yoga Pradipika, and because of the subsequent popularity of Hatha Yoga, many Hindu and western yoga teachers now accept these essentially tantric concepts within the yogic philosophy, and this is the most obvious major intersection between tantra and yoga today. The acceptance of tantric kundalini teachings into modern yoga was reinforced by the New Age movement which accompanied (and fed into) the rise of popularity of yoga in the West. 

However, Tantra and Yoga have notable points of difference. Where body consciousness is seen as the root cause of bondage in Yoga, Tantra views the body as a means to understanding, rather than as an obstruction. As a result, in India particularly, Tantra often carries quite negative connotations involving sexual misbehavior and black magic, although it must be said most forms actually follow quite mainstream social mores and this is simply an expression of prejudice. 

The actual method of Tantra is quite different to traditional Raja Yoga. It emphasises mantra (Sanskrit prayers, often to gods, that are repeated), yantra (complex symbols representing gods in various forms through intricate geometric figures), and rituals that range from simple murti (statue representations of deities) or image worship to meditation on a corpse.

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