During the period of conquest of Kalinga by emperor Ashoka, this area was known as Attabika, i.e.
a region inhabited by people of forests and mountains. He subsequently shifted his capital, first to ‘Binitpur’ (now known as Bin’ka) and then to "Son-pur" in Western Odisha.
Many small kingdoms, ruled by local chieftains, existed in ancient times, in what is now called Western Odisha. In the middle of the 10th century, Yayati, a king of the Som dynasty of South Kosal, whose capital was at Sonpur, acquired control of Utkal and shifted his capital to Yayatinagar in Utkal region.
Jajalla Deb, a ruler of the Kalchuri dynasty of Ratanpur, defeated the ruler of Sonpur and annexed it with his kingdom in 1110.
It was under the Kalchuri rulers of Ratanpur (Now in Chhattisgarh state) from 1110 to 1238. Both, eastern part of South Kosal (Western Odisha) and western part of South Kosal (Chhattisgarh) were united and ruled by the Kalchuri rulers of Ratanpur.
'Ramai Deb' of the Chauhan dynasty established his kingdom in 1320 with his capital at 'Patnagarh' in present day's Balangir Dist, and virtually ruled independently. In 15th century AD Narasingh Deva, the twelfth Raja of Patnagarh, ceded to his brother Balram Deva all the jungle country bounded on the North by the river Mahanadi, on the East by the river Tel, on the South by the Ang river, and on the west by the river Jonk.
Balram Deva, who is regarded as the founder of the Sambalpur Raj, installed Samalai, the tutelary goddess of his family. He defeated the rulers of Bamanda, Gangpur, Surguja and Ratanpur.
The State founded by Balram Deva soon became the most powerful of all the Garhjat States, and the power of the Sambalpur chiefs steadily increased, while that of Patnagarh declined.
After the death of Narasingha Deb of Patnagarh in 1547, his son 'Hamir Deb' became king. His son 'Pratap Deb' was only 7 years old, so the queen ruled in the name of his son.Taking advantage of this situation ministers started misruling.So, Balaram Deb sent his son 'Hridayanarayana Deb' to rule Patnagarh in 1550. After death of Balaram Deb, Hridayanarayana Deb became ruler of Sambalpur and Pratap Deb was again made king of Patnagarh but Patnagarh remained under Sambalpur.Western Odisha((odia:ପଶ୍ଚିମ ଓଡ଼ିଶା))is a territory in western part of Odisha, India, extending from the Kalahandi district in the south to the Sundargarh district in the northwest.Western Odisha includes the districts of Balangir, Bargarh, Boudh, Deogarh, Jharsuguda, Kalahandi, Nuapada, Sambalpur, Sonepur, Sundargarh, and Athmallik Sub-division of Angul District.Many residence refer to Western Odisha as Kosal region as well.