The Duchy of Warsaw was a feudal district duchy in Masovia, centered on the Warsaw Land. Its capital was Warsaw.

The state was established in 1310, in the partition of the Duchy of Masovia, with duke Siemowit II of Masovia becoming its first leader.Janusz Grabowski, Dynastia Piastów Mazowieckich, p. 56. It existed until 5 November 1370, when, under the rule of duke Siemowit III, duchies of Czersk, Rawa, and Warsaw were unified into the Duchy of Masovia.Anna Suprunik, Mazowsze Siemowitów, p. 29.Janusz Grabowski, Dynastia Piastów Mazowieckich, p. 89-90. It was again re-established in June 1381, in the partition of the Duchy of Masovia, with duke Janusz I of Warsaw as its first leader.Janusz Grabowski, Dynastia Piastów Mazowieckich, p. 98.Anna Suprunik, Mazowsze Siemowitów. p. 40.J. Krzyżaniakowa, J. Ochmański, Władysław II Jagiełło, p. 315. It existed until 1488, when it got incorporated into the Duchy of Czersk.

From 1310 to 1320, it was a fiefdom within the Kingdom of Poland, and from 1320 to 1385, a fiefdom of the United Kingdom of Poland, and from 1386 to 1488, a fiefdom of the Crown of the Kingdom of Poland.

List of rulers First state Siemowit II of Masovia (1310–1313) Trojden I (1313–1341) Siemowit III and Casimir I of Warsaw (1341–1349) Casimir I of Warsaw (1349–1355) Siemowit III (1355–1370)

Second state Janusz I of Warsaw (1381–1429) Bolesław IV of Warsaw (1429–1454) ( as the regent from 1429 to 1436) Casimir III of Płock, Konrad III Rudy, and Bolesław V of Warsaw (1454) (Barbara Aleksandrówna and as regents) Casimir III of Płock, Konrad III Rudy, Bolesław V of Warsaw and Janusz II of Płock (1455–1471) (Barbara Aleksandrówna and Paweł Giżycki as regents from 1455 to 1462) Bolesław V of Warsaw (1471–1481)

Citations Notes

References

Bibliography Janusz Grabowski, Dynastia Piastów Mazowieckich. Anna Suprunik, Mazowsze Siemowitów. J. Krzyżaniakowa, J. Ochmański, Władysław II Jagiełło