The name, Odisha (formerly Orissa), refers to the current state in India. But in the different era the region and parts of the region were known by different names. The boundaries of the region also has varied over the ages.

The human history in Odisha begins in the Lower Paleolithic era, as Acheulian tools dating to the period have been discovered in various places in the region.[1] The early history of Odisha is mostly obscure, with few mentions found in ancient texts like the Mahabharata, Maha Govinda Sutta and some Puranas. In 261 BCE, Ashoka of the Mauryan dynasty conquered the region in the bloody Kalinga War. The resulting bloodshed and suffering of the war deeply affected Ashoka. He turned into a pacifist and converted to Buddhism. He sent peace emissaries to various neighbouring nations. Thus as an indirect consequence, the event caused the spread of Buddhism in Asia.