Duchy of Sandomierz

State · 1139–1304 CE · at its largest around 1192 CE

Duchy in south-eastern Poland created under Boleslaw III's testament, later frequently held together with the senior duchy of Kraków.

On its lands while it lasted

• Plock (c. 1139 CE): Capital of Duchy of Masovia (1139–1351).
• Sandomierz (c. 1139 CE): Capital of Duchy of Sandomierz (1139–1304).
• Poznań (c. 1139 CE): Capital of Duchy of Greater Poland (1139–1304).
• Opole (c. 1177 CE): Capital of Duchy of Opole (1177–1304).
• Bytom (1200 CE): Capital of Duchy of Bytom (1285–1304).
• Kalisz (c. 1210 CE): Capital of Duchy of Kalisz (1210–1219).
• Kaliningrad (1255 CE): Capital of Duchy of Prussia (1526–1618).
• Königsberg (1255–1945 CE): Capital of Duchy of Prussia (1526–1618), Brandenburg-Prussia (1619–1701).
• Malbork Castle (1274 CE): Brick castle begun by the Teutonic Knights in 1274, later the order's headquarters; the largest castle in the world by land area.
• Racibórz (c. 1285 CE): Capital of Duchy of Racibórz (1285–1304).

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