Hindu temples and worship of the images permanently fixed in their garbhagṛha (sanctum sanctorum) are quite ancient. Out of the several public festivals observed by these temples, the ‘brahmot-sava’ is the biggest. (‘Brahma’ means ‘big’.) However, the orthodox belief is that the fourfaced Brahmā (the creator-god) himself conducts this festival in honour of the chief deity of the temple. Hence the name ‘brahmotsava’. Generally it is the grandest and the most spectacular of all the temple-festivals. The celebrity of a temple is often measured by the extent of the grandeur of its brahmotsava.
Āgāmic works speak of five varieties of brahmotsavas. They are:
This last one is considered as sāttvika (pure) as against the others which are either rājasika (middling) or tāmasika (inferior).
Some of the more important aspects of a brahmotsava are: bherītāḍana (beating the drum), dhvajārohaṇa (hoisting the temple flag), āvāhana (inviting the deity to the yāgaśālā or place of sacrificial rites), establishing of kalaśas (holy pots filled with water) and performance of homas.
The rathotsava (festival of taking the utsavamūrti or the procession-image in the ratha or temple car) is conducted two days before the close of the festival.
In some temples where there is the facility of a tank or a river nearby, teppotsava or boat-festival too is celebrated.