In early-15th century Grand Duke Vytautas the Great () initiated administrative reforms. He replaced regional dukes and princes with trustworthy nobles who depended on the favor of the Grand Duke. This marked the rise of Lithuanian nobility. In 1413 the Lithuanians and the Poles signed the Union of Horodło; Vilnius and Trakai Voivodeships formed in ethnic Lithuanian lands, copying the Polish system. The Eldership of Samogitia had a special semi-autonomous status. Former Slavic principalities and duchies largely preserved their old political, social, administrative features; they slowly became incorporated into the administration of the Grand Duchy. The Kiev Voivodeship was established in 1471, five other voivodeships were set up between 1504 and 1514. The Smolensk Voivodeship, the largest of all, was established in 1508, but was lost to the Grand Duchy of Moscow in 1514.