The temple celebrates dozens of festivals throughout the year. Four prime festivals, the "Brahmotsavam", are celebrated yearly. The most important of these lasts ten days during the Tamil month of "Karthikai", between November and December, concluding with the celebration of Karthikai Deepam. A huge lamp is lit in a cauldron, containing three tons of ghee, at the top of the Arunachala hills during the Deepam. To mark the occasion, the festival image of Arunachalesvara is taken around the wooden chariot around the mountain. Inscriptions indicate that the festival was celebrated as early as the Chola period (from 850 CE to 1280 CE) and was expanded to ten days in the twentieth century.