After several unsuccessful attempts to reconquer Chełmno, Duke Konrad I of Masovia in 1226 called for support by the Teutonic Knights, who indeed approached and started a Prussian campaign, after the duke promised to grant the Chełmno Land as a fief to the Teutonic Order.

In the course of the Order's decline after the 1410 Battle of Grunwald, the citizens of Chełmno, Toruń (Thorn), Lubawa (Löbau), Brodnica, Grudziądz, Nowe Miasto and Radzyń co-formed the anti-Teutonic Prussian Confederation.

After the Order's defeat, the reintegration of Chełmno Land with Poland was confirmed in the Second Peace of Thorn and together with the adjacent Lubawa Land in the east it formed the Chełmno Voivodeship of the Polish Crown, since the 1569 Union of Lublin part of the Polish–Lithuanian Commonwealth.

Voivodeship Governor (Wojewoda) seat: Regional council (sejmik generalny) Regional councils (sejmik poselski i deputacki) Administrative division: The largest city of the voivodeship was the royal city of Toruń,[3] which as one of the largest and most influential cities of entire Poland enjoyed voting rights during the Royal free elections.

[4] Other royal cities and towns were Brodnica, Golub, Grudziądz, Kowalewo, Lidzbark, Łasin, Nowe Miasto, Radzyń, Rogoźno, whereas private church towns were Chełmno, Chełmża, Kurzętnik, Lubawa and Wąbrzeźno.