With the words printed in the quotation above, the English chronicler Thomas Walsingham began his brief description of the journey of Edmund of Langley, Earl of Cambridge, to Portugal. The earl, at the head of a polyglot expeditionary force that included English, Castilian, Gascon, and Portuguese elements, set sail from the Devonian ports of Plymouth and Dartmouth on 22 June 1381, bound for Lisbon and eventually the Portuguese frontier with Castile. This force was sent to Iberia as part of John of Gaunt's grand strategy to make good his claim to the Castilian throne. The vessels that carried Edmund of Langley's army were, like the men they carried, from a mix of English, Gascon and Portuguese origins. They had been arrested by royal clerks and then modified as men-of-war for the purpose of carrying the troops to Portugal before their eventual march to the Castilian frontier.

Contemporary English chroniclers found little to report with regard to the earl of Cambridge's expedition to Iberia. This lack of commentary by contemporaries stands in stark contrast to their lengthy discussions of other naval expeditions of the Hundred Years War, such as the disaster that befell Thomas of Woodstock's fleet in its movement from Plymouth and Dartmouth to Brittany at the end of 1380 when the wretched weather in the Channel wrecked horse and troop transports alike. Like contemporaries, modern historians have said much about aspects of naval warfare in the middle stages of the Hundred Years War, but Earl Edmund's Portuguese expedition has not attracted broad attention.

Michael Postan remarked nearly half a century ago in his article, “The Costs of the Hundred Years War,” that although the numbers of Englishmen drawn into the army were substantial, “in sheer numbers even more important were the naval forces” that disrupted the normal routine of trade and commerce and occupied large numbers of sailors and masters of ships. Even if we do not accept Professor Postan's sweeping assertions as fact, his emphasis on the importance of mariners and ships during the Hundred Years War was appreciated by James Sherborne, who demonstrated that for the period from 1369–89 English seamen made “very considerable contributions” to the war effort.