The Battle of Sluys: Naval Warfare in the Hundred Years’ War

By Andrew Latham and Rand Lee Brown II

“Fierce fighting broke out on every side, archers and crossbowmen shooting arrows and bolts at each other pell-mell, and men-at-arms struggling and striking in hand-to-hand combat. In order to come to closer quarters, they had great iron grappling-hooks fixed to chains, and these they hurled into each others’ ships to draw them together and hold them fast while the men engaged. Many deadly blows were struck and gallant deeds performed, ships and men were battered, captured and recaptured.” – description of the ship-to-ship combat at the Battle of Sluys from Jean Froissart’s Chronicles.

Naval forces – typically fishing and commercial vessels – would play a key role in the titanic conflict between the realms of England and France that would later become known as the Hundred Years War. As England was essentially an island nation, King Edward III was quick to realize the need for sea power if have was to conduct a cross-channel campaign to press his claim the French throne.


However, England was at a considerable military disadvantage at the outset of this conflict in 1337 – particularly in maritime offensive capability. At this time, England possessed no formal navy of any sort, save a handful of ships owned by the king himself.

King Philip VI of France, on the other hand, was one of the few Catholic monarchs to not only maintain a small fleet of war galleys, but even a naval shipyard at the Clos de Galées located in Rouen and operated by Genoese shipwrights. Though small by modern standards, the French fleet of around twenty vessels – reinforced by Genoese mercenaries – conducted a series of devastating lightning raids across the Channel on the English coast, terrorizing English shipping and razing several key English port cities in the first few years of the war — even capturing one of King Edward’s personal ships, the Christofre. Edward learned the hard way that control of the Channel was crucial to victory in France and he set about preparing to achieve that by ending the Franco-Genoese relationship once and for all.

A miniature of the battle from Jean Froissart’s Chronicles, 15th century. BNF, fr. 2643 fol. 72.

Despite not having a formal standing navy, Edward formalized a programme of conscription that would yield him the fleet he required. Essentially, royal agents called custodes marinae went to every port in the realm with orders to conscript and confiscate any ships suited for the strategic need at the time. The owners and crews were essentially pressed into service, but not without receiving writs promising handsome compensation for their time. As a result, by 24 June 1340, Edward possessed an impressive fleet of 120-160 ships (depending on the source) loaded with men-at-arms and archers to challenge Philip’s Grand Armée de la Mer, then mustering at the Flemish harbor of Sluys.


Many historians believe that the French were gathering there for an invasion of England itself, as the Franco-Genoese fleet numbered somewhere in the vicinity of 240 vessels. However, despite the clear advantage in numbers and in a curious parallel to many of their famous land engagements of this war, the French fleet suffered from divided and inexperienced leadership. Neither of the two French admirals, Hughes Quiéret and Nicolas Béhuchet, had virtually any seafaring experience and, to make matters worse, personally loathed one another.

Upon sighting Edward’s approaching fleet, they made the bafflingly ill-advised decision to lash their ships together with large chains within the confines of the harbor entrance instead of putting out to sea where their greater numbers would have had a vastly greater effect as was recommended by their Genoese counterpart and experienced seaman, Egidio Boccanegra. Enraged at being so openly slighted, Boccanegra returned to his galleys and promptly departed, depriving the French of some of their most valuable assets right before the battle commenced. Edward arranged his ships in a formation that mirrored those he had so successfully employed in land battles – alternating ships full of men-at-arms with ships full of the lethal longbowmen, whose weapons handily outranged and outshot their crossbow counterparts on the opposing side.

The battle was joined when some lead French vessels mistook English maneuvering to be a retreat and rashly broke their formation to pursue. These isolated ships were then trapped and quickly overcome by the English, who then descended upon the rest of the French fleet still tied to their chain mooring. While the seasoned English men-at-arms performed admirably in boarding actions, the real advantage of the English fleet was in the massed firepower of the archers on the decks and up in the riggings, who rained down armor-piercing death upon the French ships. Some archers may have even fired special arrowheads designed to cut sails and rigging, further disabling the French ships from being able to maneuver.


All in all, the results were devastating for the French and by mid-afternoon, Philip’s Grand Armée de la Mer was either run aground, capsized, or captured by the English. An estimated 20,000 French soldiers and sailors perished, either in the battle itself or slain on the shores by the vehemently anti-French Flemish. Local sources noted that if the fish were given the power to speak that day after eating the drowned, they would have spoken French.

While it may be tempting to think of this as the establishment of English naval supremacy in the Channel that bears their name, it would be misleading to do so. While Sluys was indeed a smashing victory for Edward III, for which he was named “Lord of the Seas” by his court, the actual maintenance of sea power over the Channel and the Atlantic seaboard would prove far more problematic for medieval England.

This was mostly because, even during the intense fighting to follow in the Hundred Years War, England never established a full-time navy – still preferring to conscript civilian shipping as needed. This meant that French raiders again reappeared at various times, conducting guerre de course against English shipping and coastal communities, sometimes with impunity. French raiding in the south of England played a major role in instigating the Peasant’s Revolt in 1381, as English commoners balked at the apparent lack of preparation or response from the King’s government.


Finally, Henry V, of Agincourt fame, would attempt to establish a permanent navy, but would be interrupted in doing so by his untimely death in 1421. One would have to wait well into the early modern period to see British naval supremacy come into being.

Dr. Andrew Latham is a professor of political science at Macalester College in Saint Paul, Minnesota. He is the author, most recently, of a monograph entitled Medieval Sovereignty, published in 2020 by ARC Humanities Press. You can visit Andrew’s website at or follow Andrew on Twitter @aalatham

Rand Lee Brown II is a reired officer in the United States Marine Corps. Holding a Master of Arts degree in Military History from Norwich University with a focus on medieval warfare, Capt Brown has written on military history for a variety of forums, including the Marine Corps Gazette and

Click here to read more from Andrew and Rand

Further Reading:

Rogers, Clifford. War Cruel and Sharp: English Strategy under Edward III 1327-1360 (Boydell Press, 2000)


Stanton, Charles D. Medieval Maritime Warfare (Pen & Sword Books, 2015)

See also: God, leadership, Flemings and Archery: Contemporary Perspectives of Victory and Defeat at the Battle of Sluys 1340


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