After Lithuanians and Samogitians soundly defeated the joint forces of the Teutonic Knights and the Livonian Order in the Battle of Durbe in 1260, the Prussians rose against their conquerors once again.
The Teutonic Order called crusaders from Germany and Poland for help and the first large army of reinforcements arrived in January 1261.
Though a common practice, it was a tactical mistake, because Herkus Monte, the leader of the Natangians, had been educated in Germany and expected this development.
The very next day the Teutonic group dispatched to Sambia was also defeated.
This way the first wave of Teutonic reinforcements was wiped out and the Knights were in distress.