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)"): Prussia (Old Prussian: "Prūsa", German: "Preußen" , Lithuanian: "Prūsija" , Polish: "Prusy" ) is a historical region stretching from Gdańsk Bay to the end of Curonian Spit on the southeastern coast of the Baltic Sea, and extending inland as far as Masuria.
Relevant evidence: Yes