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. 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 Warwhich was fought at the banks of River Daya near present day Bhubaneswar. 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.
The region was also known to other kingdoms in region of East Indies due to maritime trade relations.
The year 1568 CE is considered a pivotal point in the region's history. In 1568 CE, the region was conquered by the armies of the Sultanate of Bengal led by the iconoclast general Kalapahad. The region lost its political identity. The following rulers of the region were more tributary lords than actual kings. After 1751, the Marathas gained control of the region for almost half a decade. In 1803, the region was passed onto the British empire. The British divided the region into parts of other provinces. In 1936, the province of Odisha was formed on the basis of populations of Odia-speaking people.