Vishnu is a major deity in contemporary Hinduism. However, during the vedic period (>2000 years ago), Vishnu was not a prominent God. While some hymns in the Rig Veda associated Vishnu with the sun, it is not until the time when two great epics – Mahabharata & Ramayana – are composed we find Vishnu being referenced to as a popular deity. A number of legendary figures from during this period and from prior to it become regarded as avatars of Vishnu. Krishna, Rama and Buddha are among the ten avatars of Vishnu. It is believed these avatars are Vishnu manifesting a portion of himself in the world when the world needs to be extricated from moral decay.
The devotees of Vishnu chant 1000 names of Vishnu as a form of worship – Hari, Vasudeva and Narayana being the more popular names.
The most common depiction of Vishnu in Hindu temples has him with his consort Lakshmi. He is also sometimes shown standing with four (or sometimes two) hands holding different objects – conch (shankha), discus (chakra), club (gada), and lotus (padma).