According to the German geographer Johann Friedrich Goldbeck (1748-1812), the town originally was named Brunsberg after Bruno von Schauenburg (1205–1281), bishop of Olomouc in Moravia, who accompanied King Ottokar II of Bohemia in 1254 and 1267 when the latter participated in the crusade of the Teutonic Knights against the Old Prussians.
It has also been suggested that the name Braunsberg might stem from Brusebergue ("camp of the Prussians"), but this notion is not documented.

In 1243 the settlement and the surrounding region of Warmia was given by the Teutonic Order to the newly created Bishopric of Warmia, whose bishop built his cathedral in the town and made it his chief residence.
The city was granted town privileges based on those of Lübeck in 1254, but in 1261 was destroyed and depopulated during the second of the Prussian Uprisings.
It was rebuilt in a new location in 1273 and settled by colonists from Lübeck.
In 1284 it was given a new town charter, again based on that of Lübeck.
However, the next bishop, Heinrich Fleming (1278–1300), transferred the chapter from Braunsberg to Frauenburg (now Frombork).

In 1296 a Franciscan abbey was built, and in 1342 a "new town" was added.
As the most important trading and harbor city in Warmia, the town prospered as member of the Hanseatic League, which it remained until 1608.

In 1440 the town was one of the founding members of the Prussian Confederation, which opposed Teutonic rule, and upon the request of which King Casimir IV Jagiellon incorporated the territory to the Kingdom of Poland in 1454.
The town pledged allegiance to the Polish King and recognized his rule in March 1454 in Kraków.
After the subsequent Thirteen Years' War the Teutonic Knights renounced any claims to the town in the Second Peace of Thorn in 1466.
Administratively it was part of the Prince-Bishopric of Warmia in the new autonomous province of Royal Prussia, later on also in the Greater Poland Province of the Polish Crown.
According to the German geographer Johann Friedrich Goldbeck (1748-1812), the town originally was named Brunsberg after Bruno von Schauenburg (1205–1281), bishop of Olomouc in Moravia, who accompanied King Ottokar II of Bohemia in 1254 and 1267 when the latter participated in the crusade of the Teutonic Knights against the Old Prussians. It has also been suggested that the name Braunsberg might stem from Brusebergue ("camp of the Prussians"), but this notion is not documented.
In 1243 the settlement and the surrounding region of Warmia was given by the Teutonic Order to the newly created Bishopric of Warmia, whose bishop built his cathedral in the town and made it his chief residence. The city was granted town privileges based on those of Lübeck in 1254, but in 1261 was destroyed and depopulated during the second of the Prussian Uprisings. It was rebuilt in a new location in 1273 and settled by colonists from Lübeck. In 1284 it was given a new town charter, again based on that of Lübeck. However, the next bishop, Heinrich Fleming (1278–1300), transferred the chapter from Braunsberg to Frauenburg (now Frombork).
In 1296 a Franciscan abbey was built, and in 1342 a "new town" was added. As the most important trading and harbor city in Warmia, the town prospered as member of the Hanseatic League, which it remained until 1608. 
In 1440 the town was one of the founding members of the Prussian Confederation, which opposed Teutonic rule, and upon the request of which King Casimir IV Jagiellon incorporated the territory to the Kingdom of Poland in 1454. The town pledged allegiance to the Polish King and recognized his rule in March 1454 in Kraków. After the subsequent Thirteen Years' War the Teutonic Knights renounced any claims to the town in the Second Peace of Thorn in 1466. Administratively it was part of the Prince-Bishopric of Warmia in the new autonomous province of Royal Prussia, later on also in the Greater Poland Province of the Polish Crown.
Braniewo