Kestutis or Kęstutis

 Kęstutis (1297–1382) was the Grand Duke of Lithuania. He was the Duke of Trakai and governed the Grand Duchy of Lithuania, 1342–1382, together with his brother Algirdas (until 1377) and his nephew Jogaila (until 1381). He ruled over the Lithuanians and Ruthenians.