Sri Saila Mallikarjuna is located in South India in the Krishna District of Andhra Pradesh (Tamil Nadu) Southwest of Madras (Chennai). This is a mountainous region and it is said that Lord Nandikeswar in the form of this mountain is considered to be holding up Lord Shiva.
When Shiva and Parvati were deciding on suitable brides for their sons, Ganesh and Muruga argued as to who would be the one to get married first. Lord Shiva said that the one who could go around the world in Pradakshinam would be married first. Pradakshinam is circling clockwise around the world so that your right side is always turned towards the person or object. This shows great reverence and respect.
Ganesh remembered that according to the ancient scriptures, going in pradkshinam around one's parents is equivalent to going once around the world. Lord Ganesh went around his parents 7 times. Lord Shiva got Siddhi and Buddhi married to Lord Ganesh. Siddhis are divine powers and Buddhi is the clear intellect and mental discrimination.
Muruga on his return was enraged and went away to stay alone on Mount Kravunja in the cave of the unmarried celibates. On seeing his father Lord Shiva coming over to pacify him; Muruga tried to move to another place. However, on the request of the higher beings Muruga stayed. The location where Lord Shiva and Parvati stayed came to be known as Sri Sailam and it is said that Lord Shiva visits Lord Muruga on the new moon and Sri Parvati visits on the full moon.