Vilnius Voivodeship
Trakai Voivodeship together with Vilnius Voivodeship was established by the Grand Duke of Lithuania Vytautas the Great in 1413 according to the Union of Horodło. Vytautas copied the Polish system of administrative division in order to centralize and strengthen the government. Trakai Voivodeship replaced the former Duchy of Trakai, which was ruled directly by the Grand Duke or his close relative (brother or son). The Duke of Trakai () was replaced by appointed officials – voivodes and his deputy castellan.