Thirumoolar in his Thirumandiram speaks of the significance of the Saiva Agamas. There are 28 Saiva Agamas, said R. Narayanan in a discourse. Lord Siva has five faces, of which Sadyojata represents the Western direction, Vamadeva the North, Aghora the South and Tatpurusha the East. The four Vedas came from these four faces. Saiva Agamas came from Isana — the fifth face. To understand the Agamas fully, one must have followed the prescribed four paths — Carya, Kriya, Yoga and Jnana. Carya is doing service in temples, and serving His devotees. Kriya is studying under a guru and then worshipping Siva. Meditating on Him is Yoga. God realisation is Jnana.
Sixty-six people learnt the Saiva Agamas, which emanated from Lord Siva. Not all of them learnt all the Agamas. The first 10 Agamas are Kamika, Yogaja, Cintya, Kaarana, Ajitha, Dipta, Sukshma, Sahasra, Amsuman and Suprabheda. Ten divine persons learnt these, each one learning one of the 10. The names of these 10 are: Pranava, Sudhaakya, Sudipta, Kaarana, Susiva, Eesa, Sukshma, Kaala, Amsu and Dasesa. Each of them taught two devotees. So 20 more people learnt the first 10 Agamas. These 20 include Trikala, Hara, Bhasma, Vibhu, Gopati, Ambika, Sarva Rudra, Trimoorthi, Hutaasana, Vaishravana, Prabhanjana, Bhima, Dharma, Ugra, Aditya, Vignesa, Sasi etc.
So, a total of 30 people learnt the first 10 Agamas, which are known as Siva Bheda. The remaining 18 Agamas were studied by 18 people, each of whom taught one person. So a total of 36 persons studied these 18 Agamas. Anadi Rudra, Paramesvara, Parvathi, Padmabhu, Vyoma, Prajapathi, Nandikesa, Brihaspati are the names of some who studied these 18 Agamas, which are known as Rudra Bheda.
