Demetrius was mentioned in medieval chronicles and in a Hungarian royal charter of 1368. According to the "Lithuanian-Ruthenian Chronicle", preserved in the "Codex Suprasliensis" and other codices, Algirdas, Grand Duke of Lithuania, invaded Podolia in 1363 and 1364 and defeated three Tatar chieftainsKutlug Bey, Hacı Bey and Demetriusin the Battle of Blue Waters in 1362 or 1363. Algirdas's invasion was the first military campaign that a European power launched in the territory of the Golden Horde.