Humans have inhabited the Plitvice Lakes area for thousands of years. It has been settled in turn by Illyrians, Japods, Celts, Romans, Avars, Slavs, Croats and Turks. Under Julius Caesar the region was incorporated as the province of Illyricum into the Roman Empire. The areas of the neighborly tribes of the Pannonians, the Liburnians and Dalmatians were united into the province of Dalmatia. Successively, the Ostrogoths took over the rule. After the Battle of Nedao in 454, the Ostrogoths were rewarded with a federation agreement with the Roman Empire.