Wikipedia
Liubartas
Demetrius of Liubar or Liubartas (also Lubart, Lubko, Lubardus, baptized Dmitry; died ~1383) was Prince of Lutsk and Liubar (Volhynia) (1323-1383), Prince of Zhytomyr (1363-1374), Grand Prince of Volhynia (1340-1383), Grand Prince of Galicia and Volhynia (1340-1349).