Battle of Sluys

The Battle of Sluys, also called Battle of l'Ecluse, was a sea battle fought on 24 June 1340 as one of the opening conflicts of the Hundred Years' War between England and France.

The encounter was during the reigns of Philip VI of France and Edward III of England, in front of the town of Newmarket or Sluis, (French Écluse), on the inlet between West Flanders and Zeeland.

During the battle Philip's navy was almost completely destroyed, giving the English fleet complete mastery over the channel. However by the end of Edward's reign the French had rebuilt their fleet and were to become a threat again.

Background
When France's Charles IV the Fair died in 1328 leaving only daughters, the nearest male relative was Edward III of England. The French establishment decided they did not want the English king on the French throne, and chose Edward's cousin, Philip, Count of Valois, to be  king of France instead. The English kings had become dukes of Aquitaine after Henry II of England married Eleanor of Aquitaine in 1152, from which point the lands in Aquitaine were held in vassalage to the French crown. Edward III did not see himself as subordinate to Philip and was reluctant to be Philip's vassal. Philip confiscated the lands that Edward held in Aquitaine, on the grounds that Edward had breached his obligation as vassal, precipitating what became known as the Hundred Years' War in 1337.

At the beginning of the war, the French had the advantage at sea. The vessels they had were ideal for swift passage across the Channel under sail or oars. Galleys had been used by the Mediterranean powers and were adopted for trade and combat by the French. The galleys could penetrate shallow harbours and were highly maneuverable and ideal for raiding or ship-to-ship combat. The huge fleet of the French, was supplemented by galleys from Genoa (some sources maintain that Castillian vessels were also part of the complement) as well as by various captured English ships including two of Edward's finest, the cogs Christopher and Cog Edward (also known as The Edward). The French were able to disrupt English commercial shipping, principally the Gascon wine and the Flanders wool trades, as well as raiding the south and eastern coasts of England at will.

The English did not at that time have a purpose built navy. What they did have was a merchant marine ship known as a cog. The cog had a deep-draught and round-hull that was driven by a single great sail set on a mast amidships. These ships were arrested from the merchant service and converted into warships by the addition of wooden 'castles' at the bow and stern, and the erecting of crow's nest platforms at the masthead, from which archers could use bows or drop stones on to enemy craft alongside. The cogs were two or three hundred tons and well able to carry many fighting men. Their high freeboard made them superior to the oared vessels in close combat, particularly when they were fitted with the castles. The king by common law was supposed to pay for the ships that he impressed into service.

Edward assembled a combined fleet at Orwell and set up his headquarters on the Cog Thomas. The Thomas set sail, with Edward on board, from the Orwell estuary on 22 June 1340,and was in sight of the roadstead at Sluys by the afternoon of the following day. Edward anchored at Blankenberge and in the evening of 23 June 1340 sent ashore  Sir Reginald Cobham, Sir John Chandos, and Sir Stephen Lambkin to reconnoitre the French fleet. They found that the enemy vessels were ranged in three compact lines and included the captured English prize, the great cog Christopher; the ships were crammed together tightly and anchored at the entrance of the Zwin (also: Zwyn) channel.

Size of the fleets
The payroll records for the English fleet have been lost, therefore historians have had to rely on the estimates of chroniclers to ascertain the size of the fleet. This has varied widely from 120 to 320 vessels. However it is believed that the English fleet that set sail from Orwell, would have numbered about 160 ships. The chronicler Thomas Walsingham stated that Edward received late reinforcements from the northern squadron led by Sir Robert Morley.

Edward III, in a letter to his son Edward, the Black Prince (written on board the Cog Thomas) dated 28 June 1340, put the size of the French fleet as 180 sail. However, contemporary French documents for the engagement still exist and these record their fleet size as 204 vessels. It was under the command of the Breton knight Hugues Quiéret, admiral for the king of France, and Nicolas Béhuchet, Constable. Part of the fleet consisted of Genoese galleys serving as mercenaries under the command of Pietro Barbavera. There are however no verifiable records of any ships from Castille in this engagement.

The battle
The dispositions of the French were made in accordance with the usual medieval tactics of a fleet fighting on the defensive. Quiéret and Béhuchet formed their forces into three or four lines chained together, with a few of the largest stationed in front as outposts. Admiral Barbavera, the experienced commander of the Genoese fleet, was concerned about this. He realised that they would lack manoverability in their anchorage and be open to attack from the ship-based English archers. He therefore advised the French commander to put to sea. Béhuchet, who as Constable exercised general command, refused to leave the anchorage as Barbavera suggested. Edward's intentions were well known, he wished to sail up the Zwin to Bruges and land his army to support his invasion plans. It is believed that Béhuchet's intention was to bar Edward's way.

The extant records report that Edward entered the roadstead at high tide on 24 June 1340, and that after maneuvering his ships to windward, sailed his fleet with the sun behind them towards the French. However, as the English fleet approached the Zwin estuary from the north west, it would appear highly unlikely that the sun would have been behind them, as modern research reveals that high tide would have been at 11:23am on the 24 June.

Edward sent his ships against the French fleet in units of three, two ships crammed with archers and one full of men-at-arms. The English ships with the archers would come alongside a French ship and rain arrows down on its decks, the men-at-arms would then board and take the vessel. The English archers, with their long bows, could accurately fire twenty arrows per minute at a range of up to 300 yards, whereas the Genoese crossbowmen could only manage two.

The battle was essentially a land battle at sea. The two opposing ships would be lashed together and the men-at-arms would then engage in hand-to-hand fighting. As the battle progressed Béhuchet's tactics proved  disastrous for the French, as it allowed the English to attack their left flank while leaving the rest of the fleet paralyzed. In a letter to his son Edward said that the enemy made a noble defense "all that day and the night after".

Many French ships were successfully boarded and captured after fierce battles. Genoese crossbowmen also managed to successfully board and capture two English ships. Edward made no mention of any actual help given him by his Flemish allies, though he said they were willing; the French claim that they joined after dark. They also asserted that the king was wounded by Béhuchet, but this is not certain, and there was no evidence other than a legendary one of a personal encounter between him and the French commander. Nevertheless it would not be improbable. It is a sure fact, though, that the King was wounded by either an arrow or a bolt during the battle.

By the end of the battle, the French fleet had been broken with the loss of only two English ships captured, and the water was reported to be thick with blood and corpses.

Aftermath
With the French navy decimated and with Edward winning success at other naval engagements, he became confident enough to dispense with a regular navy. He chose instead to overwork his mercantile marine by continually impressing the ships and neglecting to pay for them. The result was that Merchants were ruined and shipbuilding ceased. By the end of Edward's reign the French had revived their navy and were again able to dominate the channel and raid the south coast of England.