German Lusatiz), was anciently a margraviate of Germany, lying between Brandenburg, Silesia, Bohemia, and Saxony, and having an area of about 4200 square miles. It was instituted in 931, but after various changes was annexed to Bohemia in 1370. In 1635 it was ceded by Ferdinand II. to the electorate of Saxony. By decision of the Congress of Vienna, in 1815, Saxony was obliged to cede the whole of Lower, and also a portion of Upper Lusatia to Prussia. The remainder of Upper Lusatia now forms the Saxon province of Bautzen.