A royal writ from King John of England commanding his seneschals, governors, and bailiffs in Ireland to assist Reginald, King of Mann, against the Wikini (Norwegian sea rovers) and other enemies. This document illustrates early medieval relations between the English Crown and the Kings of Mann, and the strategic importance of Mann in controlling Irish Sea trade and defence. It is relevant to understanding Mann's constitutional and feudal relationship with England prior to the 1765 Revestment.