# Duke of Masovia

Duke of Masovia (Polish: Książę Mazowsza) was a title borne 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.
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.

## Dukes of Masovia and Kuyavia
### Piast dynasty
#### Partitions of Masovia and Kuyavia under Piast dynasty

The Duchy went through various border changes in the coming years, sometimes losing and sometimes gaining territory.
| Duchy of Masovia (1st creation) (1138-1275) | Duchy of Masovia (1st creation) (1138-1275) | Duchy of Masovia (1st creation) (1138-1275) | Duchy of Masovia (1st creation) (1138-1275) | Duchy of Łęczyca (1267-1351) | | | Duchy of Dobrzyń (1267-1327) | Duchy of Kuyavia (1247-1333) |
| Duchy of Czersk (1st creation) (1275-1294) | Duchy of Płock (1st creation) (1275-1294) | Duchy of Płock (1st creation) (1275-1294) | Duchy of Płock (1st creation) (1275-1294) | | | Duchy of Łęczyca (1267-1351) | | | Duchy of Dobrzyń (1267-1327) | Duchy of Kuyavia (1247-1333) |
| Duchy of Czersk (1st creation) (1275-1294) | Duchy of Płock (1st creation) (1275-1294) | Duchy of Płock (1st creation) (1275-1294) | Duchy of Płock (1st creation) (1275-1294) | Duchy of Łęczyca (1267-1351) | Duchy of Gniewkow (1287-1364) | Duchy of Inowrocław (1267-1333) | Duchy of Dobrzyń (1267-1327) | Duchy of Kuyavia (1247-1333) |
| Duchy of Warsaw (1st creation) (1313-1495) | Duchy of Warsaw (1st creation) (1313-1495) | Duchy of Rawa (1st creation) (1313-1355) | | Duchy of Łęczyca (1267-1351) | Duchy of Gniewkow (1287-1364) | Annexed to Poland | Annexed to Poland | Annexed to Poland | Annexed to Poland |
| Duchy of Warsaw (1st creation) (1313-1495) | Duchy of Warsaw (1st creation) (1313-1495) | Duchy of Rawa (1st creation) (1313-1355) | Annexed to Poland (1355-1370) | Duchy of Łęczyca (1267-1351) | Duchy of Gniewkow (1287-1364) | Annexed to Poland | Annexed to Poland | Annexed to Poland | Annexed to Poland |
| | | | Annexed to Poland (1355-1370) | Annexed to Poland | Annexed to Poland | | Annexed to Poland | Annexed to Poland | Annexed to Poland | Annexed to Poland |
| | | Duchy of Rawa (2nd creation) (1426-1459) | Duchy of Płock (2nd creation) (1381-1462) | Annexed to Poland | Annexed to Poland | Annexed to Poland | Annexed to Poland | Annexed to Poland | Annexed to Poland |
| Duchy of Czersk (2nd creation) (1471-1495) | | | Duchy of Płock (3rd creation) (1471-1495) | Annexed to Poland | Annexed to Poland | Annexed to Poland | Annexed to Poland | Annexed to Poland | Annexed to Poland |
| Annexed to Poland ||||

#### Table of rulers

| Ruler | Ruler | Born | Reign | Ruling Part | Consort | Death | Notes |
| Salomea of Berg | | 1093 Ehingen Daughter of Henry, Count of Berg and Adelaide of Mochental | 28 October 1138 – 27 July 1144 | Duchy of Masovia (at Łęczyca) | Boleslaus III of Poland March–July 1115 eleven children | 27 July 1144 Łęczyca aged 50–51 | Heirs of Boleslaus III of Poland, Salomea received a widower seat located in Masovia, while her son inherited the main duchy. |
| Boleslaus (IV) the Curly | | 1122 Third son of Boleslaus III of Poland and Salomea of Berg | 28 October 1138 – 5 January 1173 | Duchy of Masovia | Viacheslava Vsevolodovna of Novgorod 1137 three children Maria c.1170 no children | 5 January 1173 aged 50–51 | Heirs of Boleslaus III of Poland, Salomea received a widower seat located in Masovia, while her son inherited the main duchy. |
| Regency of Casimir II of Poland (1173-1176) | Regency of Casimir II of Poland (1173-1176) | Regency of Casimir II of Poland (1173-1176) | Regency of Casimir II of Poland (1173-1176) | Regency of Casimir II of Poland (1173-1176) | Regency of Casimir II of Poland (1173-1176) | Regency of Casimir II of Poland (1173-1176) | Died with no heirs. The duchy passed to his uncle and prior regent. |
| Leszek I | | 1162 Son of Boleslaus IV of Poland and Viacheslava Vsevolodovna of Novgorod | 5 January 1173 – 1186 | Duchy of Masovia | Unmarried | 1186 aged 23-24 | Died with no heirs. The duchy passed to his uncle and prior regent. |
| Casimir (II) the Just | | 28 October 1138 Sixth son of Boleslaus III of Poland and Salomea of Berg | 1186 – 5 May 1194 | Duchy of Masovia | Helen of Znojmo 1163 seven children | 5 May 1194 Kraków aged 55 | Regent of the previous. Also monarch of Poland. |
| Regency of Helen of Znojmo (1194-1200) | Regency of Helen of Znojmo (1194-1200) | Regency of Helen of Znojmo (1194-1200) | Regency of Helen of Znojmo (1194-1200) | Regency of Helen of Znojmo (1194-1200) | Regency of Helen of Znojmo (1194-1200) | Regency of Helen of Znojmo (1194-1200) | Children of Casimir II of Poland, inherited Masovia jointly, at least until 1200, when Leszek abdicated to pursue a more relevant political career at Kraków. Both were, in fact, and at different moments, monarchs of Poland. |
| Leszek II the White | | 1184 First son of Casimir II of Poland and Helen of Znojmo | 5 May 1194 – 1200 | Duchy of Masovia | Grimislava Ingvarevna of Lutsk between 1208 and 1211 three children | 24 November 1227 Gąsawa aged 42–43 | Children of Casimir II of Poland, inherited Masovia jointly, at least until 1200, when Leszek abdicated to pursue a more relevant political career at Kraków. Both were, in fact, and at different moments, monarchs of Poland. |
| Conrad I | | 1187 Second son of Casimir II of Poland and Helen of Znojmo | 5 May 1194 – 31 August 1247 | Duchy of Masovia | Agafia Yaroslavna of Peremyshl between 1207 and 1210 ten children | 31 August 1247 aged 59-60 | Children of Casimir II of Poland, inherited Masovia jointly, at least until 1200, when Leszek abdicated to pursue a more relevant political career at Kraków. Both were, in fact, and at different moments, monarchs of Poland. |
| Boleslaus I | | 1208 First son of Conrad I and Agafia Yaroslavna of Peremyshl | 31 August 1247 – 25 February 1248 | Duchy of Masovia | Gertrude of Wrocław 1232 no children Anastasia Alexandrovna of Belz 1245/47 no children | 25 February 1248 aged 39-40 | Children of Conrad I, divided their inheritance. As Boleslaus left no children, his younger brother Siemowit inherited his lands, reunifying two thirds of the main duchy. Siemowit was, however, killed in a battle against the Lithuanians, who also took his heir prisoner. |
| Casimir I | | 1211 Second son of Conrad I and Agafia Yaroslavna of Peremyshl | 31 August 1247 – 14 December 1267 | Duchy of Kuyavia | Hedwig of Greater Poland (d.c.1235) 1230 no children Constance of Wrocław 1239 Wrocław two children Euphrosyne of Opole 1257/59 four children | 14 December 1267 Inowrocław aged 55-56 | Children of Conrad I, divided their inheritance. As Boleslaus left no children, his younger brother Siemowit inherited his lands, reunifying two thirds of the main duchy. Siemowit was, however, killed in a battle against the Lithuanians, who also took his heir prisoner. |
| Siemowit I | | c.1220? Third son of Conrad I and Agafia Yaroslavna of Peremyshl | 31 August 1247 – 23 June 1262 | Duchy of Masovia (at Czersk until 1248) | Pereyaslava Danilovna of Halych 1248 three children | 23 June 1262 aged 41-42 | Children of Conrad I, divided their inheritance. As Boleslaus left no children, his younger brother Siemowit inherited his lands, reunifying two thirds of the main duchy. Siemowit was, however, killed in a battle against the Lithuanians, who also took his heir prisoner. |
| Regencies of Pereyaslava Danilovna of Halych and Boleslaus, Duke of Greater Poland (1262-1264) | Regencies of Pereyaslava Danilovna of Halych and Boleslaus, Duke of Greater Poland (1262-1264) | Regencies of Pereyaslava Danilovna of Halych and Boleslaus, Duke of Greater Poland (1262-1264) | Regencies of Pereyaslava Danilovna of Halych and Boleslaus, Duke of Greater Poland (1262-1264) | Regencies of Pereyaslava Danilovna of Halych and Boleslaus, Duke of Greater Poland (1262-1264) | Regencies of Pereyaslava Danilovna of Halych and Boleslaus, Duke of Greater Poland (1262-1264) | Regencies of Pereyaslava Danilovna of Halych and Boleslaus, Duke of Greater Poland (1262-1264) | Children of Siemowit I, divided their inheritance. Conrad was the heir in captivity by the Lithuanians, but was released two years later. Conrad left no children and his brother inherited his part. |
| Conrad II | | 1250 First son of Siemowit I and Pereyaslava Danilovna of Galicia-Volhynia | 23 June 1262 –21 December 1294 | Duchy of Czersk | Hedwig of Legnica 1265/70 one child | 21 December 1294 aged 43–44 | Children of Siemowit I, divided their inheritance. Conrad was the heir in captivity by the Lithuanians, but was released two years later. Conrad left no children and his brother inherited his part. |
| Boleslaus II | | 1253 Second son of Siemowit I and Pereyaslava Danilovna of Galicia-Volhynia | 23 June 1262 – 20 April 1313 | Duchy of Płock | Gaudemantė Sophia of Lithuania 1279 three children Kunigunde of Bohemia 1291 (divorced 1302) two children | 20 April 1313 aged 59–60 | Children of Siemowit I, divided their inheritance. Conrad was the heir in captivity by the Lithuanians, but was released two years later. Conrad left no children and his brother inherited his part. |
| Leszek I the Black | | 1241 Brześć Kujawski First son of Casimir I and Constance of Wrocław | 14 December 1267 – 30 September 1288 | Duchy of Łęczyca | Agrippine Rostislavna of Halych 1265 no children | 30 September 1288 Kraków aged 46–47 | Children of Casimir I, divided and exchanged their inheritances. The younger brothers were minors and remained under regency until 1275. Leaving no descendants, Leszek left Leczyca to his haçf-brother Casimir. Of all these brothers, Leszek and Ladislaus ruled also as dukes of Poland in different moments, but was this last one that became King of Poland in 1320. The ascension motivated more exchanges between the newly founded kingdom and this branch of the family, and a faster annexation of its domains. |
| Siemomysł | | 1245 Second son of Casimir I and Constance of Wrocław | 14 December 1267 – 24 December 1287 | Duchy of Inowrocław | Salomea of Pomerelia 1268 six children | 24 December 1287 aged 46–47 | Children of Casimir I, divided and exchanged their inheritances. The younger brothers were minors and remained under regency until 1275. Leaving no descendants, Leszek left Leczyca to his haçf-brother Casimir. Of all these brothers, Leszek and Ladislaus ruled also as dukes of Poland in different moments, but was this last one that became King of Poland in 1320. The ascension motivated more exchanges between the newly founded kingdom and this branch of the family, and a faster annexation of its domains. |
| Children of Casimir I, divided and exchanged their inheritances. The younger brothers were minors and remained under regency until 1275. Leaving no descendants, Leszek left Leczyca to his haçf-brother Casimir. Of all these brothers, Leszek and Ladislaus ruled also as dukes of Poland in different moments, but was this last one that became King of Poland in 1320. The ascension motivated more exchanges between the newly founded kingdom and this branch of the family, and a faster annexation of its domains. |||||||
| Ladislaus I the Elbow-high | | 1260 First son of Casimir I and Euphrosyne of Opole | 14 December 1267 – 2 March 1333 | Duchy of Brześć Kujawski (Kuyavia proper; within the Kingdom of Poland since 1320) | Hedwig of Kalisz 6 January 1293 six children | 2 March 1333 Kraków aged 46–47 | Children of Casimir I, divided and exchanged their inheritances. The younger brothers were minors and remained under regency until 1275. Leaving no descendants, Leszek left Leczyca to his haçf-brother Casimir. Of all these brothers, Leszek and Ladislaus ruled also as dukes of Poland in different moments, but was this last one that became King of Poland in 1320. The ascension motivated more exchanges between the newly founded kingdom and this branch of the family, and a faster annexation of its domains. |
| Casimir II | | 1261 Second son of Casimir I and Euphrosyne of Opole | 14 December 1267 – 10 June 1294 | Duchy of Łęczyca (in co-rulership in Brześć Kujawski until 1288) | Unmarried | 10 June 1294 aged 46–47 | Children of Casimir I, divided and exchanged their inheritances. The younger brothers were minors and remained under regency until 1275. Leaving no descendants, Leszek left Leczyca to his haçf-brother Casimir. Of all these brothers, Leszek and Ladislaus ruled also as dukes of Poland in different moments, but was this last one that became King of Poland in 1320. The ascension motivated more exchanges between the newly founded kingdom and this branch of the family, and a faster annexation of its domains. |
| Siemowit | | 1262 Third son of Casimir I and Euphrosyne of Opole | 14 December 1267 – 1312 | Duchy of Dobrzyń | Anastasia Lvovna of Galicia–Volhynia 1296/1300 three children | 1312 aged 49–50 | Children of Casimir I, divided and exchanged their inheritances. The younger brothers were minors and remained under regency until 1275. Leaving no descendants, Leszek left Leczyca to his haçf-brother Casimir. Of all these brothers, Leszek and Ladislaus ruled also as dukes of Poland in different moments, but was this last one that became King of Poland in 1320. The ascension motivated more exchanges between the newly founded kingdom and this branch of the family, and a faster annexation of its domains. |
| Leczyca briefly annexed to Brześć Kujawski (1294-1300) and Bohemia (1300-1306), and then joined Dobrzyń ||||||||
| Brześć Kujawski annexed to Poland ||||||||
| Regency of Salomea of Pomerelia (1287-1294) | Regency of Salomea of Pomerelia (1287-1294) | Regency of Salomea of Pomerelia (1287-1294) | Regency of Salomea of Pomerelia (1287-1294) | Regency of Salomea of Pomerelia (1287-1294) | Regency of Salomea of Pomerelia (1287-1294) | Regency of Salomea of Pomerelia (1287-1294) | Children of Siemomysl, divided their inheritance. In 1324, Leszek abdicated unexpectedly of all his inheritance to his brother Premislaus. |
| Leszek II | | 1275 First son of Siemomysł and Salomea of Pomerelia | 24 December 1287 – 1314 | Duchy of Inowrocław (at Inowroclaw proper) | Unmarried | 1340 aged 64–65 | Children of Siemomysl, divided their inheritance. In 1324, Leszek abdicated unexpectedly of all his inheritance to his brother Premislaus. |
| Premislaus | | 1278 Second son of Siemomysł and Salomea of Pomerelia | 24 December 1287 – 16 February 1339 | Duchy of Inowrocław (in Wyszogród until 1327; in Inowroclaw 1314-27; in Sieradz from 1327) | Unmarried | 16 February 1339 aged 46–47 | Children of Siemomysl, divided their inheritance. In 1324, Leszek abdicated unexpectedly of all his inheritance to his brother Premislaus. |
| Casimir III | | 1280 Third son of Siemomysł and Salomea of Pomerelia | 24 December 1287 – 13 May 1350 | Duchy of Gniewków | Unknown at least children | 13 May 1350 aged 69–70 | Children of Siemomysl, divided their inheritance. In 1324, Leszek abdicated unexpectedly of all his inheritance to his brother Premislaus. |
| Wyszogród, Inowroclaw and Sieradz annexed to Poland ||||||||
| Regency of Ladislaus I, Duke of Kuyavia and Anastasia Lvovna of Galicia–Volhynia (1312-1316) | Regency of Ladislaus I, Duke of Kuyavia and Anastasia Lvovna of Galicia–Volhynia (1312-1316) | Regency of Ladislaus I, Duke of Kuyavia and Anastasia Lvovna of Galicia–Volhynia (1312-1316) | Regency of Ladislaus I, Duke of Kuyavia and Anastasia Lvovna of Galicia–Volhynia (1312-1316) | Regency of Ladislaus I, Duke of Kuyavia and Anastasia Lvovna of Galicia–Volhynia (1312-1316) | Regency of Ladislaus I, Duke of Kuyavia and Anastasia Lvovna of Galicia–Volhynia (1312-1316) | Regency of Ladislaus I, Duke of Kuyavia and Anastasia Lvovna of Galicia–Volhynia (1312-1316) | Children of Siemowit, ruled jointly. As none of them left children, their possessions were inherited by Poland. |
| Leszek III | | c.1300 First son of Siemowit and Anastasia Lvovna of Galicia–Volhynia | 1312 – July 1316 | Duchy of Dobrzyń (in Dobrzyń nad Wisłą until 1327; at Łęczyca since 1327) | Unmarried | July 1316 aged 15–16 | Children of Siemowit, ruled jointly. As none of them left children, their possessions were inherited by Poland. |
| Ladislaus II the Hunchback | | 1303 Second son of Siemowit and Anastasia Lvovna of Galicia–Volhynia | 1312 – April 1352 | Duchy of Dobrzyń (in Dobrzyń nad Wisłą until 1327; at Łęczyca since 1327) | Anna (d. September 1349) no children | April 1352 aged 48–49 | Children of Siemowit, ruled jointly. As none of them left children, their possessions were inherited by Poland. |
| Boleslaus | | c.1305 Third son of Siemowit and Anastasia Lvovna of Galicia–Volhynia | 1312 – 1328 | Duchy of Dobrzyń (in Dobrzyń nad Wisłą until 1327; at Łęczyca since 1327) | Unmarried | 1328 aged 22–23 | Children of Siemowit, ruled jointly. As none of them left children, their possessions were inherited by Poland. |
| Dobrzyń and Łęczyca annexed to Poland ||||||||
| Siemowit II | | 1283 First son of Boleslaus II and Gaudemantė Sophia of Lithuania | 20 April 1313 – 18 February 1345 | Duchy of Rawa | Unmarried | 18 February 1345 Sochaczew aged 61–62 | Children of Boleslaus II, divided their inheritance. Siemowit left no descendants and left his county to his nephews. Trojden apparently already retained Czersk during his father's lifetime, but he inherited Warsaw after his death. Trojden also put his own son in the throne of Galicia-Volhynia, in virtue of his marriage. |
| Trojden I | | 1284 Second son of Boleslaus II and Gaudemantė Sophia of Lithuania | 20 April 1313 – 13 March 1341 | Duchy of Warsaw | Maria Yurievna of Galicia-Volhynia 1309/10 four children | 13 March 1341 Warka aged 56–57 | Children of Boleslaus II, divided their inheritance. Siemowit left no descendants and left his county to his nephews. Trojden apparently already retained Czersk during his father's lifetime, but he inherited Warsaw after his death. Trojden also put his own son in the throne of Galicia-Volhynia, in virtue of his marriage. |
| Wenceslaus | | 1293 Son of Boleslaus II and Kunigunde of Bohemia | 20 April 1313 – 23 May 1336 | Duchy of Płock | Dannila Elisabeth of Lithuania 1316 two children | 23 May 1336 Płock aged 42–43 | Children of Boleslaus II, divided their inheritance. Siemowit left no descendants and left his county to his nephews. Trojden apparently already retained Czersk during his father's lifetime, but he inherited Warsaw after his death. Trojden also put his own son in the throne of Galicia-Volhynia, in virtue of his marriage. |
| Regencies of Dannila Elisabeth of Lithuania, Siemowit II, Duke of Rawa and Trojden I, Duke of Warsaw (1336-1340) | Regencies of Dannila Elisabeth of Lithuania, Siemowit II, Duke of Rawa and Trojden I, Duke of Warsaw (1336-1340) | Regencies of Dannila Elisabeth of Lithuania, Siemowit II, Duke of Rawa and Trojden I, Duke of Warsaw (1336-1340) | Regencies of Dannila Elisabeth of Lithuania, Siemowit II, Duke of Rawa and Trojden I, Duke of Warsaw (1336-1340) | Regencies of Dannila Elisabeth of Lithuania, Siemowit II, Duke of Rawa and Trojden I, Duke of Warsaw (1336-1340) | Regencies of Dannila Elisabeth of Lithuania, Siemowit II, Duke of Rawa and Trojden I, Duke of Warsaw (1336-1340) | Regencies of Dannila Elisabeth of Lithuania, Siemowit II, Duke of Rawa and Trojden I, Duke of Warsaw (1336-1340) | |
| Boleslaus III | | 1322 Son of Wenceslaus and Dannila Elisabeth of Lithuania | 23 May 1336 – 20 August 1351 | Duchy of Płock | Unmarried | 20 August 1351 Mělník aged 28–29 | |
| Płock was temporarily annexed to the Kingdom of Poland (1351-1370), and then to Warsaw ||||||||
| Siemowit III | | 1314 First son of Trojden I and Maria Yurievna of Galicia-Volhynia | 13 March 1341 – 16 June 1381 | Duchy of Warsaw | Euphemia of Opava 1335 five children Anna of Ziębice c.1360 three children | 16 June 1381 aged 66–67 | Children of Trojden I, first ruled jointly, and, after their uncle Siemowit II's death (1345), divided their inheritance, made official in 1349. Between 1355 and 1370, Warsaw reunited the Masovian territories, but they were again divided after Siemowit III's death. |
| Casimir I | | 1329 Second son of Trojden I and Maria Yurievna of Galicia-Volhynia | 13 March 1341 – 5 December 1355 | Duchy of Rawa (at Warsaw until 1345) | Unmarried | 5 December 1355 aged 25–26 | Children of Trojden I, first ruled jointly, and, after their uncle Siemowit II's death (1345), divided their inheritance, made official in 1349. Between 1355 and 1370, Warsaw reunited the Masovian territories, but they were again divided after Siemowit III's death. |
| Rawa annexed to Warsaw ||||||||
| Ladislaus III the White | | 1327 Son of Casimir III | 13 May 1350 – 5 April 1364 | Duchy of Gniewków | Elisabeth of Strzelce 1359 no children | 29 February 1388 Strasbourg aged 60–61 | In 1364 sold his possessions to Poland, but raised himself as candidate to the Kingdom of Poland after the death of Casimir III the Great. In 1377, resigned all his claims. |
| Gniewków annexed to Poland ||||||||
| Janusz I the Elder | | 1347 First son of Siemowit III and Euphemia of Opava | 16 June 1381 – 8 December 1429 | Duchy of Warsaw | Danutė Anna of Lithuania 1371/3 four children | 8 December 1429 Czersk aged 81–82 | Children of Siemowit III, divided their inheritance. Janusz was, after 1391, Duke of Podlasie. Siemowit lost much of his domain to the Teutonic Order in 1382 (Wizna, Zawkrze, Płońsk), but gained Bełz from Poland. |
| Siemowit IV the Younger | | 1353 Second son of Siemowit III and Euphemia of Opava | 16 June 1381 – 21 January 1426 | Duchy of Płock | Alexandra of Lithuania 1387 thirteen children | 21 January 1426 Gostynin aged 72–73 | Children of Siemowit III, divided their inheritance. Janusz was, after 1391, Duke of Podlasie. Siemowit lost much of his domain to the Teutonic Order in 1382 (Wizna, Zawkrze, Płońsk), but gained Bełz from Poland. |
| Siemowit V | | 1389 First son of Siemowit IV and Alexandra of Lithuania | 21 January 1426 – 17 February 1442 | Duchy of Rawa | Margareta of Racibórz 1434/37 one child | 17 February 1442 Rawa Mazowiecka aged 52–53 | Sons of Siemowit IV, divided their inheritance. The death of Siemowit and Casimir in 1442, both without descendants, allowed Ladislaus to reunite the inheritance of his father (all but Gostynin, town that remained under Siemowit V's widow's control). |
| Casimir II | | 1401 Second son of Siemowit IV and Alexandra of Lithuania | 21 January 1426 – 15 September 1442 | Duchy of Płock (in Bełz) | Margareta of Szamotuł 26 June 1442 Turobin no children | 15 September 1442 Miączyn aged 40–41 |
| Trojden II | | 1403 Third son of Siemowit IV and Alexandra of Lithuania | 21 January 1426 – 25 July 1427 | Duchy of Płock (in Płock proper) | Unmarried | 25 July 1427 aged 23–24 |
| Ladislaus I | | 1406 Fourth son of Siemowit IV and Alexandra of Lithuania | 21 January 1426 – 12 December 1455 | Duchy of Płock (in Płock proper) | Anna of Oleśnica 1444 two children | 12 December 1455 aged 50–51 |
| Rawa (with exceptions) was annexed to Płock ||||||||
| Belz remerged in Płock ||||||||
| Regency of Danutė Anna of Lithuania (1429-1436) | Regency of Danutė Anna of Lithuania (1429-1436) | Regency of Danutė Anna of Lithuania (1429-1436) | Regency of Danutė Anna of Lithuania (1429-1436) | Regency of Danutė Anna of Lithuania (1429-1436) | Regency of Danutė Anna of Lithuania (1429-1436) | Regency of Danutė Anna of Lithuania (1429-1436) | |
| Boleslaus IV | | 1421 Son of Janusz I and Danutė Anna of Lithuania | 8 December 1429 – 10 September 1454 | Duchy of Warsaw | Barbara Olelkovna of Slutsk-Kapy 1440/5 ten children | 10 September 1454 Opinogóra Górna aged 32-33 | |
| Margareta of Racibórz | | 1410 Daughter of John II, Duke of Racibórz and Helena of Lithuania | 17 February 1442 – 5 July 1459 | Duchy of Rawa (at Gostynin) | Siemowit V 1434/37 one child | 5 July 1459 Gostynin (?) aged 48-49 | Received Gostynin as her husband's inheritance. After her death her part rejoined Płock. |
| Gostynin was annexed to Płock ||||||||
| Anna of Oleśnica | | c.1425 Daughter of Conrad V, Duke of Oleśnica and Margareta | 12 December 1455 – August 1482 | Duchy of Płock (in Sochaczew until 1476; in Koło and Mszczonów from 1476) | Ladislaus I 1444 two children | August 1482 aged 56–57 | 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. Their mother Anna, besides the regency of her sons, had also an independent seat in Sochaczew (1455–76). When this land was annexed to Poland, she received Koło and Mszczonów as compensation (1476–82). |
| 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. Their mother Anna, besides the regency of her sons, had also an independent seat in Sochaczew (1455–76). When this land was annexed to Poland, she received Koło and Mszczonów as compensation (1476–82). |||||||
| Siemowit VI | | 2 January 1446 First son of Ladislaus I and Anna of Oleśnica | 12 December 1455 – 1 January 1462 | Duchy of Płock (in Płock proper) | Unmarried | 1 January 1462 aged 15 | 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. Their mother Anna, besides the regency of her sons, had also an independent seat in Sochaczew (1455–76). When this land was annexed to Poland, she received Koło and Mszczonów as compensation (1476–82). |
| Ladislaus II | | November 1448 Second son of Ladislaus I and Anna of Oleśnica | 12 December 1455 – 27 February 1462 | Duchy of Płock (in Płock proper) | Unmarried | 27 February 1462 aged 13 | 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. Their mother Anna, besides the regency of her sons, had also an independent seat in Sochaczew (1455–76). When this land was annexed to Poland, she received Koło and Mszczonów as compensation (1476–82). |
| Płock, Koło and Mszczonów were annexed to Warsaw; Sochazew was annexed to Poland ||||||||
| Regencies of Barbara Olelkovna of Slutsk-Kapy and Paul Giżycki, Bishop of Płock (1454-1462) | Regencies of Barbara Olelkovna of Slutsk-Kapy and Paul Giżycki, Bishop of Płock (1454-1462) | Regencies of Barbara Olelkovna of Slutsk-Kapy and Paul Giżycki, Bishop of Płock (1454-1462) | Regencies of Barbara Olelkovna of Slutsk-Kapy and Paul Giżycki, Bishop of Płock (1454-1462) | Regencies of Barbara Olelkovna of Slutsk-Kapy and Paul Giżycki, Bishop of Płock (1454-1462) | Regencies of Barbara Olelkovna of Slutsk-Kapy and Paul Giżycki, Bishop of Płock (1454-1462) | Regencies of Barbara Olelkovna of Slutsk-Kapy and Paul Giżycki, Bishop of Płock (1454-1462) | Children of Boleslaus IV, ruled firstly jointly ruled jointly under regency. In 1462 they inherited the rest of Masovia, reuniting the Duchy. In 1471, they divided the inheritance. In 1495, as the last surviving brother in power, Conrad III reunited all Masovia definitely. |
| Conrad III the Red | | 1447 Third son of Boleslaus IV and Barbara Olelkovna of Slutsk-Kapy | 10 September 1454 – 28 October 1503 | Duchy of Masovia (in Czersk until 1495) | Magdalena Stawrot 1468/70 (morganatic) no children Unknown bef. 20 July 1477 (morganatic, divorced 1493?) no children Anna Radziwiłł 1496/7 four children | 28 October 1503 Osieck aged 55–56 | Children of Boleslaus IV, ruled firstly jointly ruled jointly under regency. In 1462 they inherited the rest of Masovia, reuniting the Duchy. In 1471, they divided the inheritance. In 1495, as the last surviving brother in power, Conrad III reunited all Masovia definitely. |
| Casimir III | | 10 June 1448 Fifth son of Boleslaus IV and Barbara Olelkovna of Slutsk-Kapy | 10 September 1454 – 1475 | Duchy of Płock (in Duchy of Warsaw until 1462) | Unmarried | 9 June 1480 Pułtusk aged 31 | Children of Boleslaus IV, ruled firstly jointly ruled jointly under regency. In 1462 they inherited the rest of Masovia, reuniting the Duchy. In 1471, they divided the inheritance. In 1495, as the last surviving brother in power, Conrad III reunited all Masovia definitely. |
| Boleslaus V | | 1453 Seventh son of Boleslaus IV and Barbara Olelkovna of Slutsk-Kapy | 10 September 1454 – 27 April 1488 | Duchy of Warsaw (at Warsaw proper) | Anna Radzanów 20 July 1477 (morganatic, annulled 1480) no children | 27 April 1488 Łomża aged 34-35 | Children of Boleslaus IV, ruled firstly jointly ruled jointly under regency. In 1462 they inherited the rest of Masovia, reuniting the Duchy. In 1471, they divided the inheritance. In 1495, as the last surviving brother in power, Conrad III reunited all Masovia definitely. |
| Janusz II | | 1455 Eighth son of Boleslaus IV and Barbara Olelkovna of Slutsk-Kapy | 10 September 1454 – 16 February 1495 | Duchy of Warsaw (at Ciechanów and Łomża) | Unmarried | 16 February 1495 Płock aged 39-40 | Children of Boleslaus IV, ruled firstly jointly ruled jointly under regency. In 1462 they inherited the rest of Masovia, reuniting the Duchy. In 1471, they divided the inheritance. In 1495, as the last surviving brother in power, Conrad III reunited all Masovia definitely. |
| Regency of Anna Radziwiłł (1503-1518) | Regency of Anna Radziwiłł (1503-1518) | Regency of Anna Radziwiłł (1503-1518) | Regency of Anna Radziwiłł (1503-1518) | Regency of Anna Radziwiłł (1503-1518) | Regency of Anna Radziwiłł (1503-1518) | Regency of Anna Radziwiłł (1503-1518) | Sons of Conrad III, ruled jointly. |
| Stanisław | | 17 May 1501 First son of Conrad III and Anna Radziwiłł | 28 October 1503 – 8 August 1524 | Duchy of Masovia | Unmarried | 8 August 1524 aged 23 | Sons of Conrad III, ruled jointly. |
| Janusz III | | 27 September 1502 Second son of Conrad III and Anna Radziwiłł | 28 October 1503 – 10 March 1526 | Duchy of Masovia | Unmarried | 10 March 1526 aged 24 | Sons of Conrad III, ruled jointly. |
| Anna | | c.1498 Daughter of Conrad III and Anna Radziwiłł | 10 March 1526 – 1537 | Duchy of Masovia | Stanisław Odrowąż 1536 one child | January 1557 Jarosław aged 58–59 | The last Masovian Piast. Anna was elected duchess by the nobles to maintain the independence of the Duchy. She forfeited her rights to Poland in 1537. |