The peace loving monks really just wanted a peaceful little community in which to worship God. Building on fertile land next to a wide open trading river didn't place them in a highly defensible position. Their only real defense was this tower. The doorway is very high up on the other side. The monks would take their large collection of valuables up a wooden ladder, haul the ladder up and hide in the room at the top of the tower. They got attacked - a lot unfortunately. Eventually attackers worked out that they could smoke the monks out. This meant the monks began to take their valuables and hide them in the peat bogs of this county. Only that monk would know the exact location. Unfortunately, sudden death would prevent the secret being passe on and much of it was lost. Farmers still turn up antiquities when ploughing their fields.