Both the Kingdom of Poland and Kievan…

Both the Kingdom of Poland and Kievan Rus had fought in the tenth century for the possession of Chelm Land, of which Chelm is the most important town, and after several subsequent conflicts, in about 1240 King Daniel of Galicia had made Chełm capital of an Orthodox Diocese, which resulted in the rapid development of the town.

Following the Mongol invasion of Rus', which weakened the Ruthenian states, the Grand Duchy of Lithuania, a new power in Eastern Europe, had occupied Chełm.

Polish King Casimir III had annexed the town, together with Belz, Red Ruthenia and Podolia, in 1340.

The Land of Chełm was initially united with the Land of Belz, but in 1387 King Wladyslaw Jagiello directly annexes Chelm to the Polish Crown, while …