From 1138 to 1228, part of the Duchy of Cracow and Sandomierz, belonging to the high-dukes of Poland.

Table of contents
1 Dukes of Sieradz-Leczyca
2 Dukes of Sieradz
3 Dukes of Leczyca

Dukes of Sieradz-Leczyca

after 1305 parts of the united Kingdom of Poland initially as two vassal duhies, later incorporated as Leczyca Voivodship and Sieradz Voivodship.

Dukes of Sieradz

After 1305 part of the united Kingdom of Poland as a vassal duchy, later after 1339 incorporated by the king Casimir III the Great as the Sieradz Voivodship

Dukes of Leczyca

  • 1233-1234 Konrad of Masovia (Konrad Mazowiecki)
  • 1275-1294 Casimir II of Leczyca (Kazimierz II)
  • 1329-1343 Ladislaus of Dobrzyn (Władysław Dobrzyński)

After 1305 part of the united Kingdom of Poland as a vassal duchy, later after 1343 incorporated by the king Casimir III the Great as the Leczyca Voivodship