Duke of Masovia

Duke of Masovia (Polish: Książę Mazowsza) was a title born by 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 four to five 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.

Dukes of Masovia in 1450

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 MasoviaEdit

Partitions of MasoviaEdit

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

1138–1275 Duchy of Masovia
1275–1294 Duchy of Czersk Duchy of Płock
1294-1310 Duchy of Masovia
1310-1313 Duchy of Czersk Duchy of Masovia
1313-1345 Duchy of Warsaw Duchy of Rawa Duchy of Płock
1345-1349 Duchy of Warsaw-Rawa
1349-1351 Duchy of Warsaw Duchy of Rawa
1351-1355 Annexed to Poland
1355-1370 Duchy of Warsaw-Rawa
1370-1381 Duchy of Masovia
1381-1434 Duchy of Warsaw Duchy of Płock-Rawa
1434-1442/59 Duchy of Rawa Duchy of Płock Duchy of Bełz
1442/59-1462 Duchy of Płock-Rawa
1462-1471 Duchy of Masovia
1471-1488 Duchy of Czersk Duchy of Warsaw Duchy of Płock
1488-1495 Duchy of Czersk-Warsaw
1495-1526 Duchy of Masovia

Dukes of MasoviaEdit

Piast DynastyEdit

Ruler Born Reign Death Ruling Part Consort Notes
Boleslaus (I) the Curly   1125 1138-1173 5 January 1173 Masovia Viacheslava Vsevolodovna of Novgorod
three children

after 1160
no children
Son of Bolesław III Wrymouth of Poland. Also Duke of Silesia and monarch of Poland.
Leszek I 1162 1173-1186 1186 Masovia Unmarried Son of Bolesław the Curly.
Casimir (II) the Just   1138 1186-1194 5 May 1194 Masovia 1163
seven children
Son of Bolesław III Wrymouth of Poland. Also monarch of Poland.
Helena of Moravia-Znojmo (regent)   1141 1194-1200 1202/6 Masovia Regent on behalf of her son.
Leszek II the White   1184/5 24 November 1227 Masovia Grimislava Ingvarevna of Lutsk
between 1208 and 1211
three children
Son of Casimir the Just. Also monarch of Poland, after his abdication of Masovia to his brother Conrad, in 1200, shortly after reaching majority.
Conrad I   1187/8 1200-1247 31 August 1247 Masovia Agafia Yaroslavna of Peremyshl
between 1207 and 1210
ten children
Son of Casimir the Just. Also monarch of Poland.
Boleslaus I   1208 1247-1248 25 February 1248 Masovia Gertrude of Lower Silesia
no children

Anastasia Alexandrovna of Belz
between 1245 and July 1247
no children
Son of Conrad I. Died without descendants.
Siemowit I   1224/8 1248-1262 23 June 1262 Masovia 1248
three children
Brother of Bolesław I. Killed in a battle against the Lithuanians, who also took his heir prisoner.
Pereyaslava Danilovna of Halych (regent) Before 1248 1262-1264 12 April 1283 Masovia Regents during Conrad's captivity in Lithuania.
Boleslaus, Duke of Greater Poland (regent)   1224/7 14 April 1279 Masovia Yolanda of Hungary
three children
Conrad II   1250 1264-1275 24 June or 21 December 1294 Masovia Hedwig of Legnica
one child
Released after two years of captivity. In 1275 divided the land with his brother Bolesław. After the division of the duchy he received Czersk. His death without male heirs allowed his brother to reunite the Duchy.
1275-1294 Czersk
Boleslaus II   1253/8 1275-1294 20 April 1313 Płock Gaudemantė Sophia of Lithuania
three children

Kunigunde of Bohemia
(divorced 1302)
two children
Reunited the duchy after the death of his brother, but after his own death Masovia was divided again.
1294-1313 Masovia
Trojden I   1284/6 1310-1313 13 March 1341 Czersk Maria Yurievna of Galicia-Volhynia
four children
Son of Boleslaus II, retained Czersk during his father's lifetime. After Boleslaus' death, Trojden received more lands in inheritance and made Warsaw his new capital. Put his own son in the throne of Galicia-Volhynia.
1313-1341 Warsaw
Siemowit II   1283 1313-1345 18 February 1345 Rawa Unmarried Son of Boleslaus II, retained Rawa. Left no descendants and his duchy was inherited by his nephews Siemowit III and Casimir I.
Wenceslaus I   1293/7 1313-1336 23 May 1336 Płock Dannila Elisabeth of Lithuania
two children
Son of Boleslaus II, retained Płock.
Siemowit II, Duke of Rawa (regent)   1283 1336-1340 18 February 1345 Płock Unmarried Regents in name of their nephew, Bolesław III.
Trojden I, Duke of Warsaw (regent)   1284/6 13 March 1341 Płock Maria Yurievna of Galicia-Volhynia
four children
Boleslaus III 1322/30 1340-1351 20 August 1351 Płock Unmarried Son of Wenceslaus. In 1351 Płock was annexed by the Kingdom of Poland.
Annexation to the Kingdom of Poland (1351-1370)
Casimir I   1329/31 1341-1345 26 November/5 December 1355 Warsaw Unmarried Sons of Trojden I, ruled jointly. In 1345 inherited Rawa. In 1349 divided the land between them: Siemowit received Warsaw and Casimir Rawa. After Casimir's death without descendants in 1355, Siemowit reunited Masovia. He also brought Płock from Poland in 1370. After his death the duchy was again divided between his sons Janusz I and Siemowit IV.
1345-1349 Warsaw and Rawa
1349-1355 Rawa
Siemowit III   1320 1341-1345 16 June 1381 Warsaw Euphemia of Opava
five children

Anna of Ziębice
three children
1345-1349 Warsaw and Rawa
1349-1355 Warsaw
1355-1381 Masovia
John I the Elder   1347/52 1381-1429 8 December 1429 Warsaw Danutė Anna of Lithuania
four children
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 the Younger'   1353/6 1381-1426 21 January 1426 Płock and Rawa Alexandra of Lithuania
thirteen children
Son of Siemowit III. Since 1386, was an 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 1403/6 1426-1427 25 July 1427 Płock and Rawa Unmarried Sons of Siemowit IV, ruled jointly. In 1434 the three surviving brothers divided the land: Siemowit received Rawa, Casimir received Bełz, ad Ladislaus received Płock. The death of Siemowit and Casimir in 1442, both without descendants, allowed Ladislaus to reunite the inheritance of his father.
Siemowit V 1389 1426-1434 17 February 1442 Płock and Rawa Margareta of Opava-Ráciborz
Between 15 October 1434 and 17 February 1437
one child
1434-1442 Rawa
Casimir II 1401/3 1426-1434 15 September 1442 Płock and Rawa Margareta Szamotuły
26 June 1442
no children
1434-1442 Bełz
Ladislaus I   1406/9 1426-1434 11/12 December 1455 Płock and Rawa Anna of Oleśnica
two children
1434-1442 Płock
1442-1455 Płock, Bełz and Rawa-Rawa
Anna of Lithuania (regent) c.1390? 1429-1436 3 May/1 August 1458 Warsaw Bolesław Januszowic, heir of Warsaw
three children
Daughter-in-law of Janusz I the Elder; Regent on behalf of her son.
Boleslaus IV   1421 1436-1454 10 September 1454 Warsaw Barbara Olelkovna of Slutsk-Kapy
ten children
Margareta of Opava-Ráciborz 1410 1442-1459 5 July 1459 Rawa-Gostynin Siemowit V
Between 15 October 1434 and 17 February 1437
one child
Received Gostynin as her husband's inheritance. After her death her part rejoined Płock.
Anna of Oleśnica (regent) 1425? 1455-1459 After 15 August 1482 Płock and Rawa-Rawa Władysław I
two children
Regents on behalf of Anna's sons.
Paul Giżycki, Bishop of Płock (regent) 1400 28 January 1463 Płock and Rawa-Rawa Unmarried
Siemowit VI 2 January 1446 1459-1462 31 December 1461/1 January 1462 Płock and Rawa (Rawa and Gostynin) Unmarried Sons of Ladislaus I, ruled jointly. In 1459 inherited Gostynin from their aunt Margareta. After their deaths, Masovia was again reunited by the sons of Boleslaus IV.
Ladislaus II After 31 October 1448 27 February 1462 Płock and Rawa (Rawa and Gostynin) Unmarried
Barbara Olelkovna of Slutsk-Kapy (regent) 1421 1454-1462 10 September 1454 Warsaw Bolesław IV
ten children
Regents on behalf of Barbara's sons.
Paul Giżycki, Bishop of Płock (regent) 1400 28 January 1463 Warsaw
Casimir III 10 June 1448/8 June 1449 1462 9 June 1480 Warsaw Unmarried Sons of Boleslaus IV, ruled jointly. In 1462 they inherited the rest of Masovia, reuniting the Duchy. However in 1471 they made new partitions: Casimir received Płock, however in 1475 abdicated of his lands to his brother Janusz, who hadn't any share of the land since 1471; Conrad received Czersk and Boleslaus Warsaw, which was reunited with Czersk by Conrad after Boleslaus' death in 1488. In 1495, as the last surviving brother in power, he reunited all Masovia definitely.
1462-1471 Masovia
1471-1475 Płock
Boleslaus V   c.1453 1462 27 April 1488 Warsaw Anna Radzanów
20 July 1477
(morganatic, annulled 1480)
no children
1462-1471 Masovia
1471-1488 Warsaw
John II   1455 1462 16 February 1495 Warsaw Unmarried
1462-1471 Masovia
1475-1495 Płock
Conrad III the Red   1447/8 1462 28 October 1503 Warsaw Magdaena Stawrot
no children

before 20 July 1477
(morganatic, divorced 1493?)
no children

Anna Radziwiłł
between 29 September 1496 and 2 April 1497
four children
1462-1471 Masovia
1471-1488 Czersk
1488-1495 Czersk and Warsaw
1495-1503 Masovia
Anna Radziwiłł (regent)   1475/6 1503-1518 15 March 1522 Masovia Conrad III
between 29 September 1496 and 2 April 1497
four children
Regent in name of her children.
John III   27 September 1502 1518-1526 9/10 March 1526 Masovia Unmarried Sons of Conrad III, ruled jointly.
Stanisław I   17 May 1501 1518-1524 8 August 1524 Masovia Unmarried
Anna   c.1498 1526 After 26 January 1557 Masovia Stanisław Odrowąż
one child
The last Masovian Piast. Sister of Stanislaus and John 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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