Henry V’s greatest victory (and it wasn't at the battle of Agincourt)

By sealing the Treaty of Troyes, King Charles was not only acknowledging Henry as his rightful successor but also Henry’s heirs. In other words, the two crowns were to be, for all time to come, ruled by the same king – the king of England. The treaty had swept aside the claim to the French throne of not only the Dauphin (or heir apparent) Charles, the son of Charles VI, but also of all the other male members of the Valois royal house. Worse still for the French, Henry V was to be regent while awaiting his accession to the French throne because, since 1392, Charles VI had suffered repeated mental crises.

To cement this remarkable settlement Henry married Charles’s daughter, Catherine, in Troyes on 2 June. She was crowned at Westminster Abbey on 23 February 1421, and in the following banquet, table decorations proudly proclaimed: “Through this fine marriage, war will cease.”

• Read more: A wayward prince? King Henry V’s misspent youth

So how had Henry pulled off the coup of persuading, or forcing, the French to accept the English as rightful kings of France? For William Shakespeare, there was a simple explanation: Agincourt. In his 1599 play Henry V, Shakespeare draws a direct link between Henry's most famous victory, secured in October 1415, and his diplomatic triumph at Troyes.

Henry was indeed one of England’s great military leaders. But if the years between Agincourt and the Treaty of Troyes teach us anything, it is that Henry was so much more than a brilliant soldier. He was also a talented diplomat and a ruthless opportunist. In short, he was a brilliant leader in peace as well as war, and those qualities yielded extraordinary results at Troyes.

It’s important to remember that Henry was also helped by fatal vendettas within France in the early years of the 15th century, which seriously compromised attempts to fight off English invasions. At the heart of French divisions lay a bloody rivalry between two factions battling for control of the mentally ill king: the Armagnacs, who initially rallied behind Charles VI’s younger brother, Louis, Duke of Orléans, and the Burgundians. Tensions had been rising for years, but they exploded in November 1407 when John the Fearless, Duke of Burgundy ordered the assassination of Louis. Civil war followed and soon both sides were appealing to the English for military support. Henry V’s decision to go to war in France in 1415 was surely motivated by an ambition to exploit the chaos engulfing his opponents.

A bitter siege

But Shakespeare was right in emphasising the longer term effect of Agincourt. Henry’s victory in 1415 made the French reluctant to face him in battle again. As a result, there was no major check to the campaign of systematic conquest that Henry began in Normandy on 1 August 1417. By the summer of 1418, almost all of Lower Normandy was under English control. The Norman capital, Rouen, proved a more difficult nut to crack, as a bitter six-month siege reveals. But once Rouen had accepted English rule in January 1419, much of Upper Normandy surrendered to Henry without resistance.

• Read more: 9 medieval battles more significant than Agincourt

All the while, Henry showed skill in winning the hearts and minds of his new subjects by fanning their pride in Norman identity and separatism, reviving folk memories of the old Anglo-Norman ducal past. He also ensured strong military control within his newly conquered duchy, and encouraged both his administrators and soldiers through grants of land within it – a Norman Conquest in reverse, so to speak.

Henry was a brilliant leader in peace as well as war, and those qualities yielded extraordinary results at Troyes

In the face of this determined English advance, French divisions grew wider still until in late spring 1418 they reached a new nadir with a Burgundian attack on Paris. Not only did the Burgundians seize control of the capital, they also murdered Armagnac leader Bernard d’Armagnac and forced his successor as Armagnac leader, the Dauphin Charles, into flight. As for the king, he fell under the control of the Duke of Burgundy and was moved to Troyes for his ‘safety’.

Once Henry V had taken Rouen, the Duke of Burgundy was willing to negotiate with the English. Henry too was keen to come to a settlement to consolidate his success. At the subsequent meeting at Meulan in June 1419, where Henry first set eyes on Catherine, the two sides came close to agreeing terms: the restoration to Henry of lands in south-west France granted to Edward III in the Treaty of Brétigny (1360), plus Normandy, and Henry’s marriage to Catherine with a large dowry.

Yet this settlement was never enacted. At the last minute, the Duke of Burgundy and the Dauphin chose to work towards a joint endeavour against Henry. The English king decided to continue his advance towards Paris. But a meeting of the duke and Dauphin on a bridge at Montereau on 10 September 1419 destroyed all hope of unity, for it was here that henchmen of the Dauphin assassinated Duke John – an act of revenge for the Burgundian assassinations of Duke Louis of Orléans and Bernard d’Armagnac.

A century later, in 1521 a Carthusian monk, showing King Francis I of France the damaged skull of Duke John, exclaimed: “My lord, that is the hole through which the English entered France.” He had a point: the Anglo-Burgundian negotiations that followed the murder at Montereau led to the terms that were sealed at Troyes on 21 May 1420.

A kingdom divided

The French civil war was preventing any effective resistance against the English, and Henry took advantage of the situation almost immediately, encouraged by the anxieties of the pro-Burgundian council in Paris, which was fearful of pending English attack. On 27 September 1419, English envoys presented a schedule that emphasised Henry’s claim to the French crown and which included several clauses later to be embodied in the treaty, including a marriage to Catherine – this time without the need for the French to offer a dowry. The Parisian council was amazed at Henry’s demands since they were so different from those he had put forward at Meulan only a few months earlier. But the English ambassadors explained that “things were now completely different” – by which they meant the English were now in a more powerful position.

Henry then issued an ultimatum, giving notice to the new Duke of Burgundy, Philip, that his terms had to be accepted or he would not be responsible for the consequences. Philip agreed in principle to Henry’s proposals, seeing them as a way of gaining revenge for his father’s death, and on Christmas Day he formally recognised Henry as heir to the French throne. One chronicler observed that Henry “was delighted to have an alliance with the duke since he knew that it was through him that he could achieve a marriage with Catherine, which was very agreeable to him”. Through a combination of Burgundian and English persuasion, King Charles and Queen Isabeau also gave their assent.

In the spring of 1420, an assembly of nobles, churchmen and town representatives at Troyes was told why Henry’s terms should be accepted: “First because Henry himself was wise, and a lover of God, peace and justice; he had true concern for the division and the parlous state of the kingdom of France caused by the Dauphin and his party; furthermore, the Dauphin had broken his solemn agreement with Duke John and was no longer worthy of any dignity or obedience.” The assembly declared the proposed treaty terms to be “most convenient, most profitable, and most necessary”. By 9 April the preliminaries of the treaty were agreed. All that remained was for Henry to come to Troyes for final discussions and ratifications, and for the public sealing of the treaty.

Henry was a master of realpolitik. By gaining Charles’s recognition, he boosted his own credibility in France

Throughout the negotiations, Henry had shown himself a master of realpolitik. The salient element of the treaty was not simply that Charles VI had recognised Henry as heir to the French crown, but that Henry was willing for Charles to retain the throne until his death. While Henry had enjoyed much military success to date, he was all too aware that he was in no position to take the throne by conquest. By gaining the French king’s recognition, Henry reasoned that he was boosting his own credibility and therefore the chances of acceptance by the French people. He agreed that there would be no English ‘takeover’ of France, and that he would rule according to French practice. The king and queen would be respected and supported, and would remain in France.

Intriguingly, Henry appears to have formulated the idea of such a delayed inheritance some years earlier. After the fall of Harfleur in September 1415 Henry had summoned the then Dauphin Louis to single combat. The winner, Henry suggested, should be acknowledged as the heir to Charles VI, but Louis never responded to the offer.

By the time of the sealing of the treaty of Troyes, Charles VI was not expected to live for much longer. Henry would surely be king soon. Even as regent, he knew that he could rely on the support of the Burgundians in their search for revenge. Not surprisingly, the treaty included several clauses in their favour, as well as committing Henry to the destruction of their Armagnac enemy.

Even so, Henry was aware of potential resistance within France to the terms of the treaty. As a result, the wider political community, as well as the main parties to the treaty, were required to pay public oaths to uphold the treaty, and to promise to obey Henry as heir and as king. What's more, Henry deemed it wise that there should be a formal summons to the Dauphin to face justice for the murder of Duke John, following proper French practice. After making a ceremonial entry together into Paris, deliberately timed for Advent Sunday, Charles VI and Henry held a lit de justice (a specific kind of court session). Hardly surprisingly, the Dauphin did not respond to the summons and was declared an outlaw.

Triumph and death

There were Frenchmen and women, even beyond the Armagnac group, who did not accept the validity of the treaty. For others, it offered a real hope of peace after many years of upheaval. As regent, Henry did not disappoint, both in his wise and sensitive government and in his successful military campaigns against the Dauphin’s supporters. Ironically, though, Henry’s end came through military actions. In 1422, just two years after sealing the treaty, he contracted dysentery – supposedly while besieging Meaux – and died on 31 August at the castle of Vincennes. He would never inherit the French throne despite his triumph in the Treaty of Troyes. Charles VI would follow him to the grave just two months later. And so it was that the infant Henry VI, born to Henry and Catherine on 6 December 1421, became the first king of the double monarchy of England and France. He was even crowned king in Paris, on 16 December 1431.

At first it appeared that the Treaty of Troyes might continue to thrive despite the death of its formidable creator. John Duke of Bedford, regent in France for the young Henry VI, was a well-respected warrior. Paris remained particularly loyal to the treaty: soon after the death of Henry V, the leader of its mercantile community promised his successor that in return for aid against the Dauphinists harrying Paris, “We shall abide by what is right, and be ready to obey the commands and wishes of our sovereign lord.” It helped enormously that Duke Philip of Burgundy made clear at Henry V’s death that he stood fully by the Troyes settlement: “I am ready to commit myself and do everything necessary for the good of the kingdom of France and to maintain the treaty.”

The Dauphin only became a formidable opponent after he had himself crowned as king of France in the traditional crowning place of Reims in July 1429. That gave him credibility beyond his own supporters and a real chance of challenging the ‘English’ king of France. His achievement was down to the intervention of Joan of Arc, a key figure in lifting the siege of Orléans in May 1429 and as iconic in French history as Henry V is within the English national story. Faced with increasing opposition and the defection of the Burgundians to Charles VII in 1435, Henry VI’s regime in France crumbled.

But that should not detract from what was agreed in Troyes in May 1420. Henry V was responsible for one of the most amazing treaties in history. Had it succeeded into the longer term, with the same king ruling England and France, the history of Europe might have turned out very differently indeed. The treaty proved ineffective once the English had lost most of their French lands in the early 1450s but it was not until 1801 that kings of Great Britain stopped calling themselves kings of France.

While history remembers Henry V as a warmonger, he was also a peacemaker, and a skilled one at that – aiming to resolve centuries of conflict. His vision, as expressed in the treaty terms, was that “all divisions, hatred and rancours between England and France should cease and that the two realms should enjoy in perpetuity peace, tranquillity, affection, mutual agreement and firm friendship”. Henry may be most celebrated for what he achieved on the battlefield of Agincourt. But the treaty of Troyes was surely his greatest victory.

Anne Curry is emeritus professor of medieval history at the University of Southampton. Her books include Henry V (Penguin Monarchs, 2015)

LISTEN AGAIN: You can hear Matthew Parris and guests discuss Henry V in an episode of BBC Radio 4’s Great Lives

This article was first published in the March 2020 edition of BBC History Magazine