The monks fortified the island, firstly with a wooden tower surrounded by a ditch with palisades, and then in 1327 they commenced the building of a motte and bailey fort (also known as a "peel"hence the island's modern name). This structure was, at the time, the largest of its kind in northwest England. It was probably built as a fortified warehouse to repel pirates and raiders, but it would appear to have had a measure of success in keeping the customs men at bay as well; smuggling was widespread at the time and the abbey was known to have been involved. Indeed, in 1423 an accusation was made against the Abbott of Furness that he smuggled wool out of the country from "la Peele de Foddray". The red sandstone ruins of the fort came to be known as the "Pile of Fouldrey", and are known today as Piel Castle.
