Wikipedia
Skirgaila
Skirgaila (; ; , also known as Ivan/Iwan; ca. 1353 or 1354 – 11 January 1397 in Kiev; baptized 1383/1384 as Casimir) was a regent of the Grand Duchy of Lithuania for his brother Jogaila from 1386 to 1392. He was son of Algirdas, Grand Duke of Lithuania, and his second wife Uliana of Tver.