A fishing settlement called Bydgozcya ("Bydgostia" in Latin), located in north central Poland near the confluence of the Brda and Vistula rivers, had during the early Slavic times become a stronghold on the Vistula trade routes.

It was in the thirteenth century the site of a castellany, mentioned in 1238.

The city had been occupied in 1331 by the Teutonic Knights, and incorporated into the monastic state of the Teutonic Knights.

With their signing of the Treaty of Kalisz in 1343, the Knights had relinquished the city along with Dobrzyń and the remainder of Kuyavia.

King Casimir III of Poland on April 19, 1346, grants Bydgoszcz city rights.

The city will increasingly see an influx of Jews after this date.