What was the first indian empire and what religion was spread?

The first Indian Empire was "The Mauryan Empire" founded by Chandragupta Maurya who lived from 340 to 298 BCE. Before him India was divided into many smaller states. He unified Northern India and Afghanistan into what was later known as "The Mauryan Empire".

And the first religion in the area was Buddhism, Chandragupta Maurya’s grandson Ashoka played the key role in spreading Buddhism in the Empire.