When did the cousin of the Grand Duke of Lithuania die?
Vytautas Vytautas (c. 1350 – October 27, 1430), also known as Vytautas the Great (Lithuanian: "   ", Belarusian: "Вітаўт Кейстутавіч (Vitaŭt Kiejstutavič)" , Polish: "Witold Kiejstutowicz" , Rusyn: "Vitovt", Latin: "Alexander Vitoldus") from the 15th century onwards, was a ruler of the Grand Duchy of Lithuania, which chiefly encompassed the Lithuanians and Ruthenians. He was also the Prince of Hrodna (1370–1382), Prince of Lutsk (1387~1389), and the postulated king of the Hussites.
Sophia Olelkovich Radziwill Sophia Olelkovich Radziwill (Saint Sophia of Slutsk, Princess Sophia of Slutsk; May 1, 1585 – March 19, 1612) was the last descendant of the family Olelkovich-Slutsk (princes of Slutsk and Kopyl) who were descended from Prince Algirdas. She was canonized by the Orthodox Church in 1983. The church of St. Sophia of Slutsk in Minsk is named after her.