On 28 September 1106, forty years to the day after their father landed in England, Henry I of England defeated and captured his eldest brother Robert Curthose at Tinchebrai. Henry annexed Normandy, held Robert prisoner until his death in 1134, and reunited the realm William the Conqueror had divided between his sons.
Tinchebrai was fought on 28 September 1106 in the Bocage of southern Normandy, between Henry I of England and his eldest brother Robert Curthose, Duke of Normandy. It lasted about an hour. Robert was captured on the field, along with the count of Mortain and some two hundred knights, and Henry took the duchy.
The date was not lost on contemporaries: it was forty years to the day since William the Conqueror had landed at Pevensey. Orderic Vitalis, writing in a Norman abbey, remarked that England had been won on that day and Normandy lost on it, and the symmetry gave the battle a weight in memory that its scale alone would not have earned.
William the Conqueror died in 1087 having split his inheritance: Normandy, the patrimony, to his eldest son Robert; England, the conquest, to his second surviving son William Rufus; and a large sum of silver to the youngest, Henry, with no land at all. The two halves were governed by rival brothers while most of the great families held estates in both, which left every magnate with a divided allegiance and a reason to play one ruler against the other.
Robert was a competent soldier with no talent for government — generous, easily led, and unable to hold his barons to any settlement. In 1096 he pawned the duchy to Rufus for 10,000 marks and went on the First Crusade, where he fought with real distinction at Antioch and Jerusalem. He came home in 1100 with a reputation and a wealthy wife, to find that Rufus had been shot dead in the New Forest and Henry had taken the treasury at Winchester and the crown within three days.
Robert invaded England in 1101 and got as far as a negotiated settlement at Alton: he renounced his claim to the throne for an annuity, and both sides promised to restore disinherited supporters. Neither kept faith. Henry systematically destroyed Robert’s partisans in England — Robert of Bellême was stripped of his English lands and exiled in 1102 — and then began buying Norman barons with English money.
Normandy meanwhile fell apart. Churches were plundered, castles multiplied, and the duke could neither protect his own domains nor punish those who raided them; clerical opinion, which Henry carefully cultivated, came to see intervention as a rescue. Henry campaigned in the duchy from 1104, burned Bayeux and took Caen in 1105, and in 1106 was besieging the castle of Tinchebray, held for William of Mortain, when Robert brought his army to relieve it.
Henry offered terms and Robert refused them, which the sources present as the duke’s last free choice. Henry then fought the battle in a way that was unusual for the period and characteristic of him: he dismounted the bulk of his knights to fight on foot alongside the infantry in close formation, keeping only a mounted force under Elias of Maine out of sight on the flank.
Robert’s front charged and drove into the dismounted line without breaking it. While the fight was locked, Elias brought the reserve in from the side; the ducal army collapsed almost at once. Robert of Bellême, commanding the rear, rode off without engaging — the one decision of his career that everyone recorded. The duke himself was taken, and so was William of Mortain, whom Henry never forgave and kept imprisoned for the rest of his life.
The account that carries the most weight is a letter written immediately afterwards by a priest of Fécamp who had his information locally; Orderic Vitalis and Henry of Huntingdon wrote later and inflate the numbers. Together they give an unusually clear picture of an early twelfth-century field action — dismounted knights holding, a hidden mounted reserve deciding it — which is why the battle interests military historians out of proportion to its size.
Robert was shipped to England and held for the rest of his life, at Devizes and then at Cardiff, in honourable but absolute confinement; he died in 1134 in his early eighties and was buried at Gloucester, where the painted effigy still lies. He was never tried, never deposed by any formal act, and never released, which troubled contemporaries enough that Henry took care to have the Norman magnates acknowledge his own rule as lawful.
The claim did not die with Robert’s liberty. His son William Clito, three years old in 1106 and allowed to go free, became the standing alternative to Henry for twenty years: backed at different times by Flanders, Anjou and Louis VI of France, he made Henry fight for Normandy again at Brémule in 1119 and was only removed by his death at the siege of Aalst in 1128.
It reunited the Anglo-Norman realm and kept it together for a generation. Henry governed England and Normandy as one political unit from 1106 to 1135, developing the administrative machinery — the exchequer, the itinerant justices, a treasury that could pay for allies rather than fight for them — that made the English crown the most effectively governed in western Europe.
What it could not settle was the succession. Henry’s only legitimate son drowned in the White Ship in 1120; he compelled his barons to swear to accept his daughter Matilda, and at his death in 1135 they took his nephew Stephen instead. The union Tinchebrai forced together came apart within months, and the war that followed — the Anarchy, fought out at engagements such as the Battle of the Standard in 1138 — ended with Normandy in the hands of the counts of Anjou.