Castle of Kraków bishops
|• Mayor||Zdzisław Banaś|
|• Total||38.22 km2 (14.76 sq mi)|
|• Density||140/km2 (370/sq mi)|
|Time zone||UTC+1 (CET)|
|• Summer (DST)||UTC+2 (CEST)|
In history, Sewerien was first mentioned in 1125, which was administered by the Castellan of Bytom. In 1177, Casimir II granted Sewerien to Mieszko IV Tanglefoot duke of Silesia and Racibórz, together with the duchy of Bytom. The town became a seat of a separate castellan by the beginning of the 13th century. In 1241, the Mongols burned the city, and razed the fort to ground.
In 1276, Siewierz received city status. On 26 February 1289, in front of the city gates of Siewierz, the allied forces of Władysław I the Elbow-high, then Duke of Kujawy and Mazovia, the future King of Poland, defeated the army of Henryk IV Probus, duke of Wrocław and Kraków. Henryk IV Probus accepted vassalage and protection from the Bohemian king, Wenceslaus II. He was the first Piast Silesian duke to become Bohemian vassal, leading to Bohemian annexation of most Silesia in the coming years.
In 1337, the duchy of Bytom sold Siewierz to Kazimierz I, duke of Cieszyn. In 1359 the duke of Teschen bought the city of Sewer from Bolko, Duke of Świdnica, lord of Fürstenberg, for 2,500 marks. The king Charles IV authorized the sale the same year. On 30 December 1443, Zbigniew Oleśnicki, the bishop of Kraków, bought Sewer/Siewierz from Wacław I of Teschen, who was deeply in debts then. The sale was for 6000 Prager Groschen. The bishops of Kraków became dukes of Siewierz, the duchy being not a part of Poland. The city became the seat of the bishops of Kraków, who received also the title duke of Siewierz. They also constructed a castle in Siewierz.
In 1790, near to the doom of the Polish-Lithuanian Commonwealth, the ecclesiastic duchy of Siewierz was incorporated into the Kingdom of Poland. In 1795, Sewerien, because it was a part of Silesia and its adjacent regions were annexed by Prussia, into the new province of New Silesia (in German: Neuschlesien), by the third partition of Poland. In 1800, the seat of the bishop moved away from Sewerien.
In 1807, Napoleon recreated the duchy of Siewierz (Sievers), and granted it to Jean Lannes, after Prussia was forced to cede all her acquisitions from the 2nd and 3rd partitions of Poland. After the failure of Napoleon, Siewierz was included in the Congress Poland, under Imperial Russian rule. The city declined continuously, due to the lacking of industry and communication. In 1870, it lost its city status. In 1918, Siewierz became part of the Second Polish Republic, from 1939 to 1945 of Nazi Germany. In 1962 it regained its city status.