One of the main branches of Hinduism, it is the religious and philosophical tradition centered on the worship of Shiva as the transcendental Reality. Signs of the worship of Shiva dating from as far back as 2500 B.C. have been found in archeological sites in India. Adherents of the many schools of Shaivism have produced a vast literature, which expresses both non-dual and dualistic perspectives. Expressing this non-dual understanding of Shiva, Abhinavagupta, the great teacher of Kashmir Shaivism, wrote: “The truth is, therefore, this: the Supreme Lord manifests freely all the varied play of emissions and absorptions in the sky of his own nature.”