Just returned from a trip to India and was blessed enough to visit few temples. I also had a great opportunity to converse with someone who was very knowledgeable about Tamil siddhas. He also offered me a free Tamil book ‘siddhar pattugal’. My desire is that I will be able to read and understand their writings.
I liked all the aspects about siddhas – they denounced rituals , caste based prejudices , sexism , and have eloquently stated those in their poems. They were ascetics , and all of them invariably stated that we need to find Easwar within ourselves. They came from all walks of life – Vasuki , Avvaiyar , Karaikal Ammiayar were women. Sakkili sithhar was an untouchable, but he gave diksha to Siva vakiya siddhar , who was a brahmin. Pattinathar siddhar was a merchant. Kamalamuni siddhar was a kuravar (wandering tribal). Pogar siddhar (gave diksha to Babaji Maharaj) was chinese , who settled in Tamil Nadu. Ramadevar siddhar (Yakub siddhar) was an arab who became a Siva bhaktar , who settled in Nagapattinam. All of them lived long lives .
I also learnt that the famous temples of Tamil Nadu are the Samadhi sites of these siddhas. Someone more familiar with Tamil history can shed some lights on this assertion.
I also found a link about 18 founding siddhas by googling. Enjoy reading about them.