Vishnu

Vishnu was one of the Hindu
gods. He was mentioned in the Rig Veda as
a god, but people first began to worship Vishnu as a really important
god around 300 BC. Mostly people worshipped
Vishnu by offering him flowers, or incense, or food,
or by praying to him or playing music for him. They did not usually
sacrifice animals
to Vishnu.
People thought of Vishnu as being reincarnated over and over again in
different forms. So Vishnu was often worshipped in the form of Krishna,
which was one of his reincarnations.
Another reincarnation of Vishnu was as the god Rama,
whose story is told in the great poem, the Ramayana,
written about 300 BC under the Mauryan
Empire.
Here's a short video of people worshipping Vishnu in a temple in India: