Dzogchen is both the final and ultimate teaching, and the heart of the teachings of all the Buddhas. Though generally associated with the Nyingma or Ancient School of Tibetan Buddhism founded by Padmasambhava, Dzogchen has been practised throughout the centuries by masters of all the different schools as their innermost practice. Its origins reach back to before human history, and neither is it limited to Buddhism, nor to Tibet, nor indeed even to this world of ours, as it is recorded that it has existed in thirteen different world systems.