The trebuchet was first introduced to England in 1216 during the invasion by the future king Louis VIII of France. In 1225, King Henry III of England invited an artillery engineer named Jordan, with the illuminating nickname of the `Trebuchet Maker’ to construct a large number of these engines for the royal government. By the late 1220s, trebuchets were the dominant type of stone-throwing artillery in the royal arsenal.

John’s sudden death in 1216 might have brought the end of his dynasty and a second conquest from across the Channel. Louis of France and the rebel barons who supported his claim to be king of England controlled the crucial south-east of the country: the ports of London, Southampton and Portchester and the castles of Guildford, Farnham and Winchester. It is true that access to the midlands was blocked by John’s foreign captains, Fawkes de Breauté and Engelard de Cigogné, and that the justiciar Hubert de Burgh was holding out in Dover castle. But now that John was dead, the French `were confident (in Wendover’s words) `that they had the kingdom of England in their power’. Even before John’s death French soldiers had been boasting that England was theirs and that the English had no right in the land. In principle this boast was a riposte to the English claim still to be entitled to Normandy. The French were going to redress the balance: William the Conqueror after all had taken England with a small army in 1066. Because of the power of armed knights a battle involving few troops could have decisive results, as Philip Augustus’s victory at Bouvines in 1214 and the Spanish crusaders’ victory at Las Navas de Tolosa in 1212 had recently shown. Louis’s invasion might even be seen as another Norman conquest. Certainly the Norman branches of families who had lost their English lands in 1204 took part in it, as they were excepted from the peace terms in 1217.

Louis had favourable conditions for victory: control of the centres of government, support of the rebel barons who claimed to be upholding Magna Carta, and a just cause in terms of avenging the disinherited Normans. That `hammer of kings’, Hugh bishop of Lincoln, had supposedly prophesied on his deathbed in 1200 that `this Frenchman, Philip, will wipe out the English royal stock, just as an ox plucks up grass by its roots, for already three of the sons [Henry the Young King, Geoffrey duke of Brittany, Richard I] have been eliminated and the fourth one [John] will only have a short respite’. Hugh thought this to be appropriate vengeance on the adulterous Eleanor of Aquitaine, who had insulted Louis VII of France by marrying Henry II with such alacrity. Prophecies are not facts, of course, but medieval ones often expressed significant points of view and they were much regarded in a culture which considered divine or devilish intervention a common experience in life.

The answer to the French threat in 1216 was to rely on William the Marshal. He became the hero of the hour, or at least that is the story in his biography which was written in romantic verse (that is, in French) in the 1220s. The Marshal had led an exciting and dangerous life from the time he had been handed over to King Stephen as a hostage in 1152 at the age of five or six. Reality and chivalrous romance blend in his actual life and in his verse biography in a way which it is impossible to disentangle. His recorded career is a model of chivalry: he was trained as a squire in the Tancarville family who were the master chamberlains of Normandy; as a knight he was ransomed by Eleanor of Aquitaine; he himself knighted the Young King (Henry II’s son) and fought in France with him against his father. After a pilgrimage to Jerusalem the Marshal returned to the allegiance of Henry II and saved him from defeat by killing a horse under the future Richard I. Yet he won Richard’s favour, just as he had won Henry II’s. To King John he behaved in a similarly firm way, refusing to give up his homage to Philip Augustus after 1204 and yet supporting John against the rebel barons in 1215. When John died so suddenly the next year, his will named William the Marshal first among his lay executors. The verse biography elaborates this and has John say with his last gasp: `Sirs, for God’s sake beg the Marshal to forgive me, and because I am surer of his loyalty than that of any one else, I beg you to entrust to him the guardianship of my son, for the land will never be held by anyone except with his help.’ The Marshal was reluctant to take on an almost hopeless cause but at last he was persuaded by the sight of the helpless child, the future Henry III, and by his sense of honour.

John’s men buried him at Worcester and went to Gloucester where the pathetic dignity of the future king, then aged nine, caused them to burst into tears. The boy seemed, as a poet put it with pardonable exaggeration, a `tiny spark of minute beauty, the sole hope of the torn kingdom’, like the star of Bethlehem. With dubious legality John’s men immediately crowned their little king as Henry III in Gloucester abbey with an improvised gold circlet, for they had no archbishop of Canterbury (Langton was in Rome and had been thought a traitor by John), no Westminster abbey (Louis held London), and no regalia (some of it had been lost in John’s disaster crossing the Wash and the rest was inaccessible in Westminster abbey). During the coronation dinner a messenger rushed in to say that the Marshal’s castle at Goodrich only twelve miles away was being attacked by Louis’s partisans.

The Marshal confided to his knights that he seemed to be embarking on a sea without bottom or shore. They replied that even if the worst happened and Louis took the whole of England, there was still an honourable course open to them by seeking refuge in Ireland. Heartened by this, the Marshal told his men that he would carry the little king on his shoulders from island to island and country to country and would not fail him even if he had to beg for his bread. The sentiments expressed here in the verse biography are not so much those of the Dunkirk spirit as of the knights errant in contemporary romances who pledge themselves to superhuman quests. The Marshal’s motives in upholding Henry III were presumably more complex than this. Nevertheless, as the verse biography argues, Henry’s cause might have foundered at the start if it had not been championed by the Marshal with his reputation as one of the best knights in Europe. This gave the regime prestige, and the Marshal stood as a focus of loyalty in terms of European chivalry as well as of English custom and feudal law.

Support for the boy king, however, did not depend as exclusively on the Marshal as his biography suggests. Like other apparently simple medieval narratives, the biography is a work of art which skilfully presents its author’s and hero’s point of view. Other elements favouring Henry can readily be cited. First of all, John’s death deprived his opponents of the personal cause of their rebellion. Instead of a tyrant they were now resisting a helpless boy, who was as entitled to his inheritance as any other heir. Magna Carta (clauses 2-6) had shown the importance the barons attached to laws of inheritance by specifying the rights of heirs immediately after the claims of the church. Secondly, the boy had the official backing of the new pope, Honorius III, through the legate Guala. He had added papal authority to the makeshift coronation ceremony at Gloucester by presiding at it, and furthermore within a month of John’s death he set his seal along with the Marshal’s to the revised text of Magna Carta, which was issued by the new government to all magnates and royal officials. This reversal of Innocent III’s condemnation deprived the rebels of another of their grievances, yet it did not release them from excommunication. On the contrary, Guala made the struggle against Louis into a holy war. The royalist forces wore the white cross of crusaders, they were absolved of all their sins before going into battle, and recruits were described as converts. The precedent for launching a crusade against fellow Christians had been established eight years earlier by Innocent III when he authorized the Albigensian crusade against the Cathar heretics of southern France. That was a frightening precedent, as a crusade meant that the enemy were considered infidels and were therefore given no quarter. Henry III’s troops were to show that this was what they too meant by a crusade when they sacked Lincoln and committed other atrocities in 1217.

A third element favouring the royalists in 1216 was the character of the men they had on their side in addition to the Marshal and the papal legate. They were few but formidable. First there were John’s foreign captains of whom the two most important – the Norman exile Fawkes de Breauté and the Poitevin aristocrat and troubadour Savari de Mauléon – had been named among John’s eight lay executors. Of great experience and the king’s personal tutor was the Poitevin bishop of Winchester, Peter des Roches. Then there was the justiciar Hubert de Burgh, who independently of the Marshal had refused to surrender to Louis at Dover when told of John’s death. Thirdly, there were loyal English nobles like Ranulf earl of Chester, and John’s agents of long standing such as William Brewer. The king’s side lacked numbers but not prestige nor experience.

Decisive victory for Henry III came in 1217 in the land battle at Lincoln in May and the sea battle off Dover in August. Battle was joined at Lincoln to prevent the French, who had won control of East Anglia, from penetrating northwards. It was an overwhelming victory for Henry’s side despite their inferior numbers: the count de Perche, the French commander, was killed and numerous knights were taken prisoner. The captain responsible for the surprise stratagem of attacking from within Lincoln castle was Fawkers de Breauté. The sea battle off Dover was thought even more crucial than Lincoln by both Louis and his opponents because it lost the French their access to Kent and London.

THE FAIR OF LINCOLN, 20 May 1217

In the face of a royalist army of 406 knights, 250 or 317 mercenary crossbowmen and an unknown but small number of foot-sergeants, a combined army of rebel barons and their French allies besieging Lincoln castle withdrew within the old walled Roman portion of the city, having mistakenly supposed that the royalist force was in fact larger than their own, which numbered 611 knights and 1,000infantrymen. (This error resulted from the royalist commander, William le Marshal, having left a number of standards with his baggage-train, which from a distance therefore resembled a substantial body of troops.) The royalists were nevertheless able to enter Lincoln via a postern in the castle and also by breaking through an ‘ancient’ blocked gateway in the west wall, surprising the rebels between the castle and the cathedral. The royalist crossbowmen, under Fawkes de Brébuté, sallying from the castle, were repulsed, but the knights were successful in overrunning the rebels’ siege-engines and routing the Frenchmen in a street-fight, killing their commander, the Comte de Perche. The rebels’ flight was hampered at a narrow gate by a panic-stricken cow, as a result of which some 3-400 knights and 3 rebel earls were captured by the victorious royalists, whose own losses totalled just one knight and a handful of infantry.

DOVER, 24 August 1217

Abandoning his own siege of Dover following the defeat of his northern forces at Lincoln, Prince Louis (later Louis VIII) of France, to whom the rebel barons had offered the English crown, summoned reinforcements from Calais. These sailed over 900-strong in 70 nefs and 10 large warships under Eustace the Monk, the majority of them doubtless in the warships with their supplies and equipment in the nefs. They were intercepted én route to London by an English fleet of 16 Cinque Ports vessels and 20 smaller craft commanded by the justiciar Hubert de Burgh.

These managed to get to windward of the larger French fleet and then bore down on it from behind, laying down a heavy barrage of crossbow-fire and then throwing powdered quicklime, which choked and blinded the French. One by one the French vessels were overtaken and boarded, Eustace’s own being surrounded by 4 English ships when it was unable to fire its trebuchet because of a severe list. Some others sank, their sides ‘perforated’ (either by missiles or as a result of collisions), and only 15 ships are said to have escaped. Eustace was captured and unceremoniously beheaded on his ship’s rail. As a direct result of this decisive defeat Prince Louis, with his lines of communication cut, renounced his claim to the throne and evacuated his troops from England.

Matthew Paris has Hubert de Burgh, the justiciar and castellan of Dover, say, `I beseech you by the blood of Christ to allow me to hang rather than give up the castle to any Frenchman, for it is the key of England.’ Despite the nationalist bias of Matthew Paris (and of his predecessor Roger Wendover), these events should not be seen in simplistic terms as victories of the English over the French. This would be absurd, since the most effective of Henry III’s captains, Fawkes de Breauté, was a Norman, and the Marshal himself was Norman by upbringing and remained throughout his life – in his opinion at least – a true vassal of Philip Augustus as well as of the English king. Nevertheless this hard-fought struggle with Louis of France, coming on top of the loss of Normandy, polarized the difference between English and French interests and encouraged a sense of apartness on both sides of the Channel. Such apartness was foreign to the whole life experience of international knights like the Marshal and it was foreign too to the Poitevin and papal influences which shaped the education of the new king, Henry III. He could not have felt that his throne had been saved for him by the English, still less by the French of Paris, but primarily by people of southern (technically Occitan) speech who had come like his mother from south of the Loire or like Guala from Italy.

Although in the autumn of 1217 a formal peace was made with Louis, and another revised issue of Magna Carta (together with a new Charter of the Forest) symbolized settlement at home, the Marshal did not think that anything permanent had been achieved. The only solution he could see when he lay dying in 1219 was to entrust the kingdom to the pope in the person of his new legate, Pandulf:

Car n’a teil gent en nule terre

Comment il a dedenz Engleterre

De divers corages chascuns . . .

[Because there are no people in any land

like those in England,

where each person has his own opinion . . .]

That comment came from a man whose memory of strife extended back to Stephen’s reign, but it would apply equally well to the next fifty years and the struggles of Henry III with his barons.

Every Christian knight wished to die in Jerusalem. To the Holy Sepulchre the Marshal had borne the cloak of the Young King in accordance with his oath more than thirty years before. He himself was appropriately buried in that evocation of the Holy Land in England, the round church of the London Temple, which had been dedicated by the patriarch Heraclius of Jerusalem in 1185. The Marshal’s biographer gives Philip Augustus the last word: `The Marshal was truly the most loyal man I ever knew in any place where I have been.’ Such praise was possible from the king of France because the Marshal, through his conduct as a knight, stood above national rivalries. The Marshal symbolized old-fashioned idealism.