This article is about the administrative divisions of Lithuania. Grand Duchy of Lithuania (1251–1569) In the earliest stages of the formation of the Lithuanian state, the area included several "lands" (Lithuanian: plural – , singular – ), such as Nalšia, Deltuva and Lietuva (as well as others), each ruled by a regional duke. When King Mindaugas () unified the state, he killed, expelled, or subjugated most of the regional dukes. The lands were either added to the new ruler's domain or granted to members of his family. As the Grand Duchy of Lithuania expanded into Slavic lands, title to the acquired principalities was given to the Grand Duke's offspring or to others of his relatives. For example, Mindaugas granted Black Ruthenia with its center in Navahrudak to his son Vaišvilkas; Gediminas Grand Duke of Lithuania from 1316 to 1341, sent his brother Fiodor to Kiev. This system had major disadvantages: the principalities remained semi-independent with loose ties to the central government. Rulers of these principalities could operate as powerful rivals to the Grand Duke, a situation that led to frequent power-struggles. 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. Voivodeships (Lithuanian: plural – , singular – ), ruled by appointed officials – voivodes, were further subdivided into powiats (Lithuanian: plural – , singular – ). Major administrative reforms took place in 1564–1566 in preparation for the second Statute of Lithuania of 1566 and the overhaul of the judicial system. The entire territory of the Grand Duchy, with exception of Samogitia, was divided into 12 voivodeships. Grand Duchy of Lithuania (1569–1795) Just before the Union of Lublin (1569), the four voivodeships of (Kiev, Podlaskie, Bracław,