The Prussians besieged many castles that the Knights had built and could not send large armies to fight in the west. Prussians were not familiar with Western European siege tactics and machinery and relied on siege forts, built around the castle, to cut the supplies to the garrisons. The Teutonic Knights could not raise large armies to deliver supplies to the starving garrisons and smaller castles began to fall.
The Prussians encircled numerous strongholds constructed by the Knights, which they were unable to support with large armies in the west. The Prussians lacked expertise in Western European siege warfare and employed fortified outposts surrounding the castles to restrict supplies to the besieged garrisons. Consequently, the Teutonic Knights were unable to assemble sufficient forces to deliver sustenance to the famished garrisons, resulting in the collapse of smaller fortresses.