Duchy of Kuyavia

The Duchy of Kuyavia was a district principality in central Europe created in the course of the thirteenth century in the region of Kuyavia, after the inheritance of the Kingdom of Poland was divided among partial duchies by the will of Duke Boleslaw III Wrymouth in 1138. Kuyavia was the tribal area of the Goplans, whose political centre lay at Kruszwica. The region was connected with Greater Poland from the tenth century and with the Duchy of Masovia from 1138. In 1231 the duchies of Sieradz and Leczyca were separated from it, and in 1233 it became an independent duchy under Duke Casimir I. Further partitions in 1267 and 1314 split it into the sub-duchies of Brzesc, Inowroclaw and Gniewkowo. After Wladyslaw I Lokietek began reuniting the Polish duchies, Kuyavia lost its sovereignty after 1306 and became a vassal. During the Polish-Teutonic War the Teutonic Order occupied it in 1332 and returned it by the Peace of Kalisz in 1343. It was later administered as two voivodeships.