Gautama was a Hindu before his enlightenment.
Updated Answer:
The Buddha did not mean to start any religion; what he wanted to do is bring people to happiness through enlightenment. In the process of bringing his teachings to the world by his followers the Buddhist religion was born. It should be noted that we Buddhists do not worship Buddha as any form of a deity.
He did not start Buddhism, his followers did and they added stuff to it that was not taught by Buddha, like the false stuff in the sutras.
The Buddhist Religion was founded by a man called Siddhartha Gautama.
Siddhartha Gautama founded the religion , Buddhism!
In the year 528 BCE, in Bodhgaya, India, when Siddhartha Gautama, The Buddha, became enlightened.
During Siddhartha Gautama's lifetime a form of Brahmanism which lead to Hinduism, based upon the Vedic religion was the predominate religion.
Siddhartha Gautama founded Buddhism .
Buddhism. Siddhartha Gautama is one of the major Buddhas.
Gautama Buddha.
Buddhism
the founder of the Buddhism religion.
Buddhism
moggalana
Siddhartha Gautama made up Buddhism, and then had missionaries bring it to different country's.