King of Rhovanion
From Tolkien Gateway
King of Rhovanion was a title claimed by Vidugavia, a prince of the Northmen, in the 13th century of the Third Age. However, even if he was the most powerful of the many Northern princes, as far as we know he never truly unified all the Northmen under his claimed kingship. Vidugavia's own realm, the "Kingdom of Rhovanion", was between Greenwood and the River Running.