Vilnius Voivodeship
The last Duke of Lithuania () was Vytautas the Great, who, as a result of the 1392 Astrava Treaty, received the Duchy from Jogaila, who, in turn, had inherited it from his father Algirdas. Since 1397, the Duchy had had the status of an Eldership, comparable to that of the Eldership of Samogitia. After the administrative reform of 1413 by Vytautas, based on the Union of Horodło, the Duchy became part of the newly established Vilnius Voivodeship of the Grand Duchy of Lithuania.