During the Middle Ages, the island was populated by monastic communities. By the 16th century, however, the island was uninhabited and used by pirates as a refuge and base. In 1565, Helier de Carteret, Seigneur of St. Ouen in Jersey, received letters patent from Queen Elizabeth I granting him Sark as a fief in perpetuity on condition that he kept the island free of pirates and occupied by at least forty men who were of her English subjects or swore allegiance to the Crown. This he duly did, leasing 40 parcels of land (known as "Tenements") at a low rent to forty families, mostly from St. Ouen, on condition that a house was built and maintained on each parcel and that "the Tenant" provided one man, armed with a musket, for the defence of the island. The 40 tenements survive to this day, albeit with minor boundary changes. A subsequent attempt by the families to endow a constitution under a bailiff, as in Jersey, was stopped by the Guernsey authorities who resented any attempt to wrest Sark from their bailiwick.