Śaivism. One of the major theistic traditions of medieval Hinduism, worshipping Śiva or one of his forms or symbols such as the liṅga. Although difficult to generalize about, because of its diversity, Śaivism tends to be more ascetic than Vaiṣṇavism. The origins of Śaivism are probably non-Vedic and its roots may lie in the pre-Aryan culture of the Indus Valley, where seals have been found depicting an ithyphallic, horned god, in a yogic posture and surrounded by animals. This may be a precursor of Śiva who is lord of yogis and animals. However, Śaiva literature only flourished with the Śaiva Purāṇas (4th–9th cents. CE) which are mainly concerned with mythology, and the Śaiva-Āgamas, which are primarily concerned with initiation, ritual, yoga, mantra, and temple-building.

Various Śaiva sects developed, ranging from those who adhered to Smārta orthodoxy to those who flouted it. The following sects can be distinguished: (i) Pāśupatas, the earliest Śaiva sect, along with a subsect, the Lakulīśa Pāśupata, who took an ‘animal’ vow (vrata) of asceticism, bathing in ashes, and engaging in antisocial behaviour; (ii) Kāpālikas, cremation-ground dwellers who carried a skull and performed antinomian practices; (iii) Kālāmukhas, ascetics closely associated with the Pāśupata; (iv) Vīraśaivas or Liṅgāyats, who may have developed out of the Kālāmukhas, and who worshipped Śiva in the form of the liṅga; (v) Kashmir Śaivism or Trika, so called because of its threefold category of God (Śiva), energy (śakti), and individual (aṇu); (vi) Saiva Siddhānta, a dualist system which became bhakti-oriented with the Tamil bhakti poets, the Nāyanṃārs; (vii) Smārta, orthodox Śaivism which adhered to the varnāśrama-dharma advocated in the smṛti literature, such as the law books of Manu and Kalpa Sūtras, and regarded Śiva as one of the five central deities to be worshipped (pañcayatana-pūja); and (viii) Nātha or Kanphata yogis, a sect traditionally founded by Gorakhnātha, combining Pāśupata Śaivism with Tantric and Hatha yoga.

Śaivism spread throughout India: Trika in Kashmir, Śaiva Siddhānta in the Tamil-speaking south, Vīraśaiva in the Kannada-speaking south, and Pāśupata in Gujarat. Today Śaivism is especially prevalent in Madras State. Śaiva ascetics are distinguished by their long matted hair, sometimes piled on top of their heads, three horizontal marks smeared on the forehead, the trident which they carry, and the ashes in which they are often covered. Śaiva temples and pilgrimage sites are found throughout India from the Amarnāth cave in Kashmir where there is an ice liṅga, to the Viśvanāth temple at Vārānasi and the Rauleswaram temple at the southernmost tip of India.