What is a Siddha?

In Western literature, a Siddha refers to "one who is accomplished".

In ancient times, the Siddhas emerged from the Kapalikas, who were ascetic Pashupatas during the sixth century. In the following, this text refers to the Siddhas (and Kapalikas) in various traditions of Maha Matsyendra Nath. Today, not much of the authentic Siddha and Kapalika traditions is available outside Kaulantak Peeth.