Vaidotas was a son of what ruler of medieval Lithuania who was the Duke of Trakai?
Vaidotas: Vaidotas or Wojdat (fl. Vaidotas:  1362) was a son of Kęstutis, Grand Duke of Lithuania. Kęstutis:  He was the Duke of Trakai and governed the Grand Duchy of Lithuania, 1342–82, together with his brother Algirdas (until 1377), and with his nephew Jogaila (until 1381).
i don't know