Question: What is the name of the ancient people first described by a Roman historian in his treatise that is adjacent to Prussia?
Sentence (from "Prussia (region)"): Since the military conquest by the Soviet Army in 1945 and the expulsion of the inhabitants it divided between northern Poland (most of the Warmian-Masurian Voivodeship), Russia's Kaliningrad exclave, and southwestern Lithuania (Klaipėda Region).
Relevant evidence: No