duchy · Poland, Lithuania and Russia

Duchy of Plock

1275 CE – 1495 CE (approx.) · capital Plock

The northern Masovian duchy around the old Piast city of Plock, a Polish vassal until its incorporation in 1495.

Origins

In 1275 the Duchy of Masovia was split, and the part centred on Plock, an early Piast capital and bishopric on the Vistula, went to Boleslaw II of Masovia. For two centuries Plock was sometimes reunited with the rest of Masovia and sometimes ruled as a separate duchy.

Rule and society

Plock was an old episcopal city with a Romanesque cathedral containing Piast tombs. Its dukes balanced between Poland, Bohemia and the Teutonic Order: Wenceslaus of Plock did homage to John of Bohemia in 1329. From 1351 the Masovian dukes were vassals of the Polish Crown.

Decline and legacy

The last duke of Plock, Janusz II, died in 1495, and King John I Albert incorporated the duchy into the Kingdom of Poland (1385-1569). The rest of Masovia followed in 1526.

Lineage

Duchy of Masovia 1138 CE – 1526 CEDuchy of PlockKingdom of Poland (1385-1569) 1385 CE – 1569 CE

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Cite this page
APA
The Epoch Institute. (2026). Duchy of Plock. In The Epoch Institute States Register. https://the-epoch-institute.org/state/duchy-of-plock
MLA
“Duchy of Plock.” The Epoch Institute States Register, The Epoch Institute, 2026, https://the-epoch-institute.org/state/duchy-of-plock. Accessed .
Chicago
The Epoch Institute. “Duchy of Plock.” The Epoch Institute States Register. 2026. https://the-epoch-institute.org/state/duchy-of-plock.
Harvard
The Epoch Institute (2026) ‘Duchy of Plock’, The Epoch Institute States Register. Available at: https://the-epoch-institute.org/state/duchy-of-plock (Accessed: ).

Last reviewed October 2026Random state ↻