King William I of England is better known to history as William the Conqueror. He won consistently on the battlefield, conducting five campaigns, fighting some nine major battles and directing at least 17 sieges during his 40-year military career. From his first conflict in 1047 as William II, Duke of Normandy, he triumphed every time but one—namely, the siege of the castle at Sainte-Suzanne, in northwest France, which lasted from 1084 to 1086. The remarkably well-preserved remains of William’s siege camp, just north of town, are among the best surviving examples of 11th century field fortifications anywhere in the world.

Born around 1028, William was the illegitimate son of Robert I, Duke of Normandy, and Herleva, a tanner’s daughter. When his father died in 1035, young William, referred to irreverently as “the Bastard,” succeeded to the dukedom. While still a minor William was embroiled in a series of internal power struggles, but at age 19, with the support of King Henry I of France, he took decisive control of Normandy. He spent the next two decades fighting to suppress revolts and challenges to his authority, ultimately launching his famous cross-channel invasion of England and defeating King Harold II at the Battle of Hastings. William was crowned king of England in London’s Westminster Abbey on Christmas Day 1066. But that marked only the first stage of the Norman Conquest. William fought on in various locations throughout the British Isles until 1072. Then he spent most of the next 15 years crossing back and forth from Britain to France, putting down opposition to his rule on both sides of the English Channel.

William claimed the French province of Maine (the present-day departments of Sarthe and Mayenne, just south of Normandy), a piece of strategic territory coveted by the dukes of Normandy and Brittany and the counts of Anjou. Maine, led by viscount Hubert II de Beaumontau-Maine, revolted against William in late 1083, and, as he always did, the Conqueror moved immediately against the rebellion. Rather than facing William in the open, Hubert withdrew to his strongly fortified castle at Sainte-Suzanne. In early 1084 William first attempted to take the castle by storm, but when that failed, he resorted to the type of set-piece siege of which he was a master.

William established his siege camp on the grasslands of Beugy along the River Erve, a half-mile north of the castle and just out of range of Hubert’s heavy weapons. William’s position comprised two rectangular fortifications in line, each roughly the size of a modern football field. Both positions were open on their eastern sides and surrounded on the other three sides by 30-foot-high palisades constructed of earth and rocks and capped by wooden watchtowers. Ringing the complex was a dry moat and a line of sharpened stakes. The moat also divided the two positions, with a drawbridge connecting them. It was the type of siege camp William had used so many times before. Local historians, however, believe there is evidence to suggest that rather than building Camp de Beugy from scratch, William may have improved and reinforced an older Gallo-Roman or Celtic camp.

The siege turned out to be more than William had bargained for. Hubert’s castle was strong, had plenty of supplies and its own source of water. It even boasted a subterranean gristmill. Over the next two years the attackers took more casualties than the defenders, while Hubert’s men captured and held for ransom several powerful Norman and English lords. Meanwhile, knights and men-at-arms from Aquitaine, Burgundy and other French provinces rallied to Hubert’s cause. The defenders increased in strength, while the attackers diminished. In spring 1086 William broke off the siege and came to a negotiated settlement.

Sainte-Suzanne thus became the only castle William the Conqueror failed to take. But having stabilized the situation in Maine, William was able to turn his attention to his ongoing dispute with King Phillip I of France, who was William’s nominal feudal overlord. In July 1087 William advanced into the Vexin region of France and sacked the town of Mantes. In the process, however, the 59-year-old, grossly overweight William was thrown from his horse, sustaining severe internal injuries from the pommel of his saddle. He died from his injuries that September in Rouen, France, ending one of the most spectacular military careers of the Middle Ages.

And while Sainte-Suzanne held out against William, it later fell victim to advances in military technology. In 1425, during the Hundred Years’ War, English bombards (early cannon) reduced its walls, and the English occupied it for 14 years. Today the castle ruins are an integral part of Sainte-Suzanne’s walls—forming one of the most picturesque walled towns in France. A half-mile away most of the original palisades of William’s siege camp still stand. Registered as a historic monument in 1937, Camp de Beugy is a poignant reminder of the Conqueror’s only battlefield failure.


Originally published in the January 2015 issue of Military History. To subscribe, click here.