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.
Grand Duke Sergei Alexandrovich of Russia Grand Duke Sergei Alexandrovich of Russia ("Сергей Александрович"; May 11, 1857 – February 17, 1905) was the fifth son and seventh child of Emperor Alexander II of Russia. He was an influential figure during the reigns of his brother Emperor Alexander III of Russia and his nephew Emperor Nicholas II, who was also his brother in law through Sergei's marriage to Elizabeth the sister of Tsarina Alexandra.