Duke of Masovia

Dukes of Masovia in 1450

The Dukes of Masovia were the sons and descendants of the Polish Duke Bolesław III Wrymouth. In accordance with the last will and testament of Bolesław, upon his death his lands were divided into 4-5 hereditary provinces distributed among his sons, and a royal province of Kraków reserved for the eldest, who was to be High Duke of all Poland. This was known as the fragmentation of Poland. Subsequent developments lead to further splintering of the duchies.

The following is a list of all rulers of the Duchy of Masovia and its parts. Although not all incumbents listed here had titular rights to the title of Duke of Masovia, they are all listed as such for simplicity's sake.

Also take note that some of the dates are merely approximate and the ownership of certain lands might be disputed. Finally, this table does not include lands ruled by dukes of other parts of partitioned Poland or Wenceslaus II and Wenceslaus III.

Duchy of Masovia

Partitions of Masovia

The Duchy went through various border changes in the coming years, sometimes losing and sometimes gaining territory.

      Duchy of Masovia

In 1233, the Duchy of Kujavia of emerged from Masovia.

      Duchy of Kujavia

In 1313, Masovia is divided in the Duchies of Płock, Czersk and Rawa.

      Duchy of Czersk       Duchy of Rawa       Duchy of Płock

In 1327, Kujavia is annexed by Poland

In 1349, Warsaw emerged form Czersk

      Duchy of Warsaw

In 1434, Belz emerged form Płock,tobe annexed again in 1442

      Duchy of Belz

In 1462, Rawa is annexed to Poland. The same happens with Płock in 1495.

Konrad III reunites Czersk and Warsaw, to recreate the Duchy of Masovia, annexed by Poland in1526.

Dukes of Masovia

Piast Dynasty

Ruler		Reign	Ruling Part	Notes
Bolesław the Curly		1138-1173	Masovia	Son of Bolesław III Wrymouth of Poland. Also Duke of Silesia and monarch of Poland.
Leszek I		1173-1186	Masovia	Son of Bolesław the Curly.
Casimir the Just		1186-1194	Masovia	Son of Bolesław III Wrymouth of Poland. Also monarch of Poland.
Leszek II the White		1194-1200	Masovia	Son of Casimir the Just. Ruled jointly with his brother Conrad I. Also monarch of Poland.
Conrad I		1194-1247	Masovia	Son of Casimir the Just. Ruled jointly with his brother Leszek II until 1200. Also monarch of Poland.
Casimir I		1233-1267	Kujavia	Son of Conrad I. His father granted him with the Duchy of Kujavia in 1233. After his death, the duchy is divided in Inowrocław and Brześć Kujawski. As Brześć Kujawski was already annexed by the Teutonic Order since 1228, only the duchy of Inowrocław will be mentioned here.
Bolesław I		1247-1248	Masovia	Son of Conrad I.
Siemowit I		1248-1262	Masovia	Brother of Bolesław I.
Conrad II		1262-1294	Masovia
Siemomysł		1267-1271	Kujavia-Inowrocław	Son of Casimir I. 1st time.
Bolesław the Pious		1271-1278	Kujavia-Inowrocław	Ruled jointly with Leszek the Black since 1273.
Leszek I the Black		1273-1278	Kujavia-Inowrocław	Ruled jointly with Boleslaus the Pious.
Siemomysł		1278-1287	Kujavia-Inowrocław	Son of Casimir I. 2nd time.
Leszek II		1287-1314	Kujavia-Inowrocław	Son of Siemomysl. Ruled jointly with his brothers Przemysł and Casimir II. 1st time
Przemysł		1287-1314	Kujavia-Inowrocław	Son of Siemomysl. Ruled jointly with his brothers Leszek II and Casimir II. 1st time
Casimir II		1287-1314	Kujavia-Inowrocław	Son of Siemomysl. Ruled jointly with his brothers Przemysł and Leszek II.
Bolesław II		1294-1313	Masovia	Divided the Duchy among his sons.
Trojden I		1313-1341	Czersk	First ruler of Czersk. Son of Boleslaus II.
Leszek II		1314-1324	Kujavia-Inowrocław	Ruled alone. 2nd time
Siemowit II		1313-1345	Rawa	First ruler of Rawa. Son of Boleslaus II.
Wenceslaus I		1313-1336	Płock	First ruler of Płock. Son of Boleslaus II.
Przemysł		1324-1327	Kujavia-Inowrocław	Ruled alone. 2nd time. In 1327, Kuyavia is annexed by the Kingdom of Poland.
Bolesław III		1336-1351	Płock	Son of Wenceslaus. In 1351 Płock was annexed by the Kingdom of Poland.
Casimir I		1341-1349	Czersk	Son of Trojden I. Also duke of Warsaw and Rawa.
Casimir I		1345-1349	Rawa	Also duke of Czersk and Warsaw.
Casimir I		1349-1355	Warsaw	First duke of Warsaw.
Siemowit III		1349-1370	Czersk	Brother of Casimir I. Also duke in Rawa and Warsaw.
Siemowit III		1355-1370	Rawa	Also Duke in Czersk and Warsaw.
Siemowit III		1349-1370	Warsaw	Also duke in Rawa and Czersk.
Siemowit III		1370-1381	Masovia	Brought Płock from Poland in 1370, reuniting the duchy of Masovia, but after his death it was divided between his sons Janusz I and Siemowit IV.
Janusz I		1381-1429	Warsaw	son of Siemowit III, since 1386 hereditary vassal of Poland, after 1391 Duke of Podlasie. Although the division, the duchy of Czersk remained annexed to the duchy of Warsaw.
Siemowit IV		1381-1426	Płock	Son of Siemowit III. Although the division, the duchy of Rawa remained annexed to the duchy of Płock. Since 1386, hereditary vassal of Poland, and, although having lost much of his domain to the Teutonic Order in 1382 (Wizna, Zawkrze, Płońsk), he gained other duchies (Bełz) from Poland.
Trojden II		1426-1427	Płock	Son of Siemowit IV. Ruled jointy with his brothers Casimir II, Władysław I, and Siemowit V.
Władysław I		1426-1455	Płock	Son of Siemowit IV. Ruled jointy with his brothers Casimir II, Trojden II, and Siemowit V until 1434
Casimir II		1426-1434	Płock	Son of Siemowit IV. Ruled jointy with his brothers Trojden II, Władysław I, and Siemowit V.
Siemowit V		1426-1434	Płock	Son of Siemowit IV. Ruled jointy with his brothers Casimir II, Władysław I, and Trojden II. Also duke of Rawa.
Bolesław IV		1429-1454	Warsaw	Until 1436 regency of his mother, Anna Feodorovna, between 1440 and 1444 only as Duke of Podlasie
Casimir II		1434-1442	Bełz	In 1434 Bełz emerged from Płock, to be annexed again in 1442.
Siemowit V		1434-1442	Rawa	In his reign Rawa had a briefperiod of independence, but after his death, Rawa rejoined Płock.
Bolesław V		1454-1488	Warsaw	Son of Bolesław IV. Ruled jointly with his brothers Conrad III, Casimir III and Janusz II, until 1471. In this year, Boleslaus V loses Czersk for his brother Conrad the Red.
Conrad III the Red		1462-1471	Warsaw	Son of Boleslaus IV. Ruled jointly with his brothers Conrad III, Casimir III and Janusz II.
Casimir III		1462-1471	Warsaw	Son of Boleslaus IV. Ruled jointly with his brothers Conrad III, Casimir III and Janusz II.
Janusz II		1462-1471	Warsaw	Son of Boleslaus IV. Ruled jointly with his brothers Conrad III, Casimir III and Janusz II.
Siemowit VI		1455-1462	Płock	Son of Władysław I. Ruled jointy with his brother Władysław II.
Władysław II		1455-1462	Płock	Son of Władysław I. Ruled jointy with his brother Siemowit VI.
Conrad III the Red		1462-1471	Płock
Casimir III		1471-1475	Płock
Janusz II		1475-1495	Płock	In 1495 Płock is annexed by the Kingdom of Poland.
Conrad III the Red		1471/1488/1495-1503	Masovia	Reunited the duchies which remained independent (Czersk and Warsaw, gained between 1471 and 1488) to recreate the Duchy of Masovia, in 1495.
Stanisław I		1503-1526	Masovia	Ruled jointly with his brother Janusz III.
Janusz III		1503-1526	Masovia	Ruled jointly with his brother Stanisław I.
Anna		1526	Masovia	The last Masovian Piast. Sister of Stanislaus and Janusz III. Anna was elected duchess by the nobles to maintain the independence of the Duchy. It was unsuccessful, because, in the same year, Masovia was annexed to the Kingdom of Poland.

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