Mazovian

The Mazovians were the Lechitic West Slavs of Mazovia, on the middle Vistula around Płock and Warsaw. Mieszko I incorporated them into Poland in the late tenth century.

On the fragmentation of 1138 Mazovia became a duchy under a Piast cadet line; in 1226 Duke Conrad I called in the Teutonic Knights and enfeoffed them with Chełmno Land. The duchy became a Polish fief in 1351 and passed fully to the Crown in 1526. In 1596 Sigismund III Vasa moved the royal capital to Warsaw from Kraków.

The partitions of 1793 and 1795 gave Mazovia to Prussia, with a south-eastern strip to Austria; in 1815 it passed to Russian-ruled Congress Poland. From the late Middle Ages Mazovian settlers moved into southern Prussia, where as Masurians they adopted Protestantism. The Mazovian dialect became the leading dialect of standard Polish.