The cradle of the town was one of the islands created by Brda River separating its main current. Originally, at place of today's town there was a castellan burg city called Budegac, of which the first mentions are dated back to 1238. The task of the burg city was to protect crossing the river and to defend borders of Mazovia, first against Prussia and later against Knights of the Cross.
Bydgoszcz received the civic rights in 1346 from Polish king Casimir the Great. Since then the quick flourishing of Bydgoszcz started; the brick town was built as a greenfield project, with waterworks, eight churches, king's castle, bailey, gates, towers, and mint. The salt and corn trades were being developed, as well as, the educational system; mills and granaries were being erected.
In the 17th century, as a result of the Swedish Deluge, Bydgoszcz was occupied by Swede people, and the castle underwent total destruction. The town lost its greatness and significance.
The 18th century brought another changes in the history of Bydgoszcz. Between 1772-1806 and 1815-1920, as a result of the First Partition of Poland, the town was incorporated in Prussian annexation. During those times, the town started to develop again and regain its economic significance thanks to the building of Bydgoszcz Channel. The town became then an inside land port joining Brda and Wisła rivers with Noteć and Warta Rivers. The town started to regain its significance not only thanks to water communication but also thanks to developing railway communication and the intensive development of industry and banking. The developing culture and cultivated sports tradition had also their great influence on Bydgoszcz consolidation.
The period of the Second World War was a very difficult time for Bydgoszcz since on September 1939 German army marched in the town and in retaliation for the so-called „Bloody Sunday" the time of terror, public executions of thousands of people; first of all Polish intelligentsia, and exportation inside Reich and to concentration camps started. During those times Bydgoszcz (as Bromberg) was incorporated into Gdansk/West Prussia province as a seat of the district by Germany. The town has been liberated on 26th January 1945.