A letter of protection issued by King Henry III to King Olave of Man in 1218, instructing him not to interfere with Furness Abbey, which was under royal patronage. The document appears in the Monumenta de Insula Manniae collection and illustrates the feudal relationship between the English Crown and the Kings of Man, as well as ecclesiastical privileges in the medieval period. This provides context for understanding pre-Revestment Manx sovereignty and the Crown's historical claims over the island.