An ancient royal city Radhanagar was a well-designed city, bearing mud rampart same as other ancient cities in India like Ujjain, Kosambhi and Sisupalgarh. Ashoka's Dhauli Rock Edict indicates that Kalinga's royal headquarters during Asokan period was 'Tosali'. As per the recent Radhanagar excavation, a number of inscriptions and other corroborative evidences suggest Radhanagar as the capital city of 'Tosali'. The ruins of the Radhanagar Fort have been unearthed during the recent excavation.
The excavation has also exposed black-slipped inscribed pot sherds. These pot sherds inscriptions, datable 3rd century and 2nd century BC, read as 'Tosali Nagara' and 'Tosali Nagar', 'Kalinga Ranga Go', 'Kanakamuni' and Nagaro.