The Battle of Sluys And The Medieval Struggle For Control Of The Sea

The Battle of Sluys And The Medieval Struggle For Control Of The Sea

We have been finding out a bit about medieval disasters recently, it made me think about just how dangerous warfare, particularly at sea, could be during the Middle Ages.  So I thought we could explore the Battle of Sluys, one of the most devastating naval battles of the medieval period. The battle took place on the 24th of June 1340 near the port of Sluys in what is now Belgium. It happened during the early part of the Hundred Years’ War between England and France.

Image info:

Artist: Loyset Liédet

Title: Battle of Sluys, miniture

Date: 15th century

Collection: Bibliothèque nationale de France

The battle happened because both England and France were struggling for control of the English Channel. King Edward III of England needed safe sea routes so that he could move soldiers and supplies to the continent. The French hoped to weaken the English by threatening an invasion and by cutting off English trade. Tension between the two countries had been building for years, mostly over land, power, and Edward’s claim to the French throne. A major clash at sea felt inevitable.

The French fleet gathered near Sluys and chained many of their ships together to form what they thought would be a strong defensive barrier across the harbour entrance. They had a large fleet which was made up of warships, merchant vessels, and hired Genoese ships. Thousands of sailors, knights, archers, and soldiers were on them. Medieval ships were quite often packed tightly with people of all ages. Experienced knights fought alongside teenage squires, common sailors, and young archers who may only have been in their mid to late teens. Life at sea was already dangerous before any battle even began.

Edward III sailed with a large English fleet and arrived off the coast. Chroniclers suggest the battle lasted for many hours, possibly from late morning into the evening. The English had several advantages. Their ships were more mobile, and English longbowmen proved to be devastating to the French. As the fleets closed together, arrows rained down onto the French ships. Once the vessels locked together, they were forced into brutal hand-to-hand fighting. Many men met an horrific end.

The French defensive formation actually worked against them. Because so many vessels had been tied together, it became difficult to manoeuvre or escape once the panic began to spread. The English were able to attack ship after ship in succession. Edward III fought aggressively and he inspired confidence among his men, but confusion appears to have spread through parts of the French fleet.

The loss of life was catastrophic. Medieval chroniclers often exaggerated numbers, but thousands were believed to have died. Some estimates suggest over 15,000 French sailors and soldiers may have lost their lives, although the real figure was probably lower. Many men were unable to save themselves because of the heavy armour after they had fallen into the water. English losses were far smaller but still significant. Around 190 French ships were believed to have been captured, destroyed, or sunk.

The English victory changed the course of the war. Control of the Channel gave Edward III much greater freedom to invade France and continue his campaigns overseas. It also damaged the French naval strength for many years after and it reduced the immediate threat of a French invasion of England.

Unlike battles on land, there was often no escape at sea. If your ship sank, the cold water usually became your grave.

Do you think the French defeat at Sluys was unavoidable once they chained their fleet together, or could the battle have ended very differently with another strategy?