Czersk Land in the context of "Mińsk Mazowiecki"

Czersk (Polish pronunciation: [t͡ʂɛrsk] ) is a settlement in the administrative district of Gmina Góra Kalwaria, within Piaseczno County, Masovian Voivodeship, in east-central Poland. The village also lies on the Czersk Lake (size: 9 hectares), which is an oxbow lake of the Vistula.

Czersk was an important settlement in the past and is one of the oldest Mazovian cities, famous for ruins of a medieval castle constructed in the late 14th century. It was a royal town of the Crown of the Kingdom of Poland in the past. In 1247–1526, it was the capital of the Duchy of Czersk, one of medieval Polish duchies. After incorporation of Mazovia into Poland (1526), the duchy was turned into the Czersk Land (see ziemia), part of Masovian Voivodeship (1526–1795). The Land of Czersk was divided into four counties - those of Czersk, Grójec, Garwolin (since 1539), and Warka. Czersk itself was the seat of castellans, who also were senators of the Polish–Lithuanian Commonwealth.

The Duchy of Czersk was a feudal district duchy in Masovia, centered on the Czersk Land. Its capital was Czersk.

The country was established in 1275, in the partition of the Duchy of Masovia, with duke Konrad II becoming its ruler. After his death, the duchy was unified with the Duchy of Płock, forming the Duchy of Masovia, on 24 June 1294. The state was again reestablished in 1310, with Trojden I, as its first ruler. It existed until 5 November 1370, when, under the rule of duke Siemowit III, duchies of Czersk, Rawa, and Warsaw were unified into the Duchy of Masovia. It was once again reestablished in 1471, from the part of the territories of the duchies of Płock and Warsaw. In 1488, it incorporated the Duchy of Warsaw, into its territory. It existed until 1495, when, with the incorporation of the Duchy of Płock into the Kingdom of Poland, it remained the only state in Masovia, and subsequently, got reformed into the Duchy of Masovia.