This is the story of Buttermilchthurm or Buttermilk tower. Once it was located in Marienburg in Prussia. Now it lies in Malbork area in Poland where we find ruins of a Teutonic castle too. One powerful Teutonic knight lived in that castle. He had ordered some buttermilk for himself from the neighbouring village. But the peasants jeered at his message-carriers. Two men from the village carrying a large barrel full of buttermilk arrived at the knight’s castle only after a few days. The enraged knight imprisoned those two farmers in one tower. He kept them locked there till they drank all the buttermilk from the barrel. The tower is called Buttermilk tower since then.
We have heard another story as well: the inhabitants of a neighbouring village had to make a road to the building site spending a fortune. Through the road they carried gallons of buttermilk instead of water to prepare the lime. The mortar they prepared this way was more than what they needed for the road. Hence a tower was built using that mortar later. Obviously the tower was named Buttermilk tower.