1415: The battle of Agincourt

Henry’s ultimate objective, and his obligation as Edward’s heir, was the French crown. More immediately and realistically, he tried to force territorial concessions from the elderly and insane French monarch, Charles VI, and his quarrelsome nobility: it was the best time to invade France. Henry and Charles exchanged ambassadors over many months, but the French could not agree to ever-increasing English demands. Meanwhile, Henry was planning to shock the French with his power. By mid-March 1415, Charles realised that invasion was coming and negotiations could only delay it. In April and May Henry proclaimed that “we, with God’s help, are about to go overseas to recover and regain the inheritances and just rights of our crown, which, as everyone agrees, have long been unjustly withheld”.

At the same time, Henry’s enterprise put great strains on England, its men, money and loyalties, especially since he might be absent for as long as a year. These strains showed themselves during 1414–15; the way in which they were managed helped to ensure astonishing successes for the English which continued even after the king’s early death (1422).

The army of 1415 was mostly recruited in central and southern England, and the king’s lands in Lancashire, Cheshire and south Wales provided its mainstay, archers. Though the Welsh revolt petered out after 1409, Glyn Dwr was at large until 1416 and there was resentment which had to be overcome if the king wanted to impose war taxation in Wales and raise Welsh soldiers. Thus, soon after he became king, Henry aimed to draw a line under the revolt. He even made overtures to Glyn Dwr in July 1415, a month before embarkation. Service in France and loyalty to the king benefited Welsh soldiers on their return and, in the longer term, reconciled Welsh families to English rule.

The Irish question

The crown’s second dominion, Ireland, was also a problem. Glyn Dwr tried to ally with independent Irish chieftains who resented Anglo-Irish lords and English governors in Dublin, and might assist England’s French and Scottish enemies. Moreover Ireland, more so than Wales, was a drain on English resources; when Henry V gave priority in men and money to the French war, the lordship of Ireland gradually fell under the control of Anglo-Irish lords. This detached Ireland from effective English rule during the rest of the century.

The separate kingdom of Scotland was a greater threat. From the 14th century, the Auld Alliance between France and Scotland gave every English king who planned to campaign in France pause for thought that the Scots might launch raids, or worse, across the border. Henry V inherited one advantage from his father: King James I had been a prisoner in England since 1406. Yet this did not deter the Scots, for the Duke of Albany, Regent of Scotland, was not keen to negotiate James’s return, even though his own son, Murdach, was also imprisoned in England. In November 1414 Parliament took steps to defend Berwick and the borders, and Henry tried to come to terms with Albany by exchanging Murdach for Henry Percy, heir to the earldom of Northumberland, who had been in Scottish hands since 1402. This agreement would have been a useful insurance in 1415. But the exchange was postponed and shortly before Henry embarked for France, French envoys arrived in Scotland (22 June); a month later a Scottish force crossed the border and the English retaliated. The French war increased tension between England and Scotland, and Scots even served in French armies after 1419.

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Of course, Henry had to stamp his authority on England if he were to campaign in France – especially so early in his reign. His father Henry IV seized the crown from Richard II in 1399 but this act, which founded the Lancastrian dynasty, did not go unchallenged and he spent much of his reign fighting rebellions. When Henry V succeeded in 1413, some claimed that the deposed Richard II was still alive, and others believed that Edmund Mortimer, Earl of March, was his rightful heir. Henry also faced trouble from Lollard heretics inspired by John Wycliffe (died 1384), whose calls for church reform were regarded as traitorous, especially when, in January 1414, the king’s friend, Sir John Oldcastle, joined a rising. Parliament passed anti-Lollard legislation, and early in 1415 the execution of heretics in London gripped the public and the city chroniclers – and helped Henry harness the Church in support of his war.

A plot to kill the king

Oldcastle escaped and by August 1415 was causing trouble in the Welsh borderland, just when a plot against the king was being hatched. These threats to Lancastrian rule were not coordinated but Henry V’s war preparations gave them focus. The plot aimed to kill the king at Southampton and place the young Earl of March on the throne; but it was nipped in the bud, and the Agincourt victory ended for a generation all serious challenges to Henry and his son, Henry VI, that used the revolution of 1399 as justification. The leading plotters were the Earl of Cambridge, Lord Scrope of Masham and Sir Thomas Grey of Northumberland, hoping that March would attract support in Wales and Scotland. At the last moment (31 July), March himself revealed all to the king and the leaders were summarily executed; Henry left it to Parliament in his absence to endorse what he had done. The treatment of the plotters and the presence of most nobles in the English army reflect Henry’s success in mastering his enemies and reconciling dissidents. Victory at Agincourt induced Church and Parliament to support future campaigns.

Agincourt entered English (and Welsh) mythology because contemporaries celebrated it, exaggerated Henry’s achievement and saw God’s hand in it all, and because Shakespeare’s vision has been compelling drama ever since. But it was close-run; Henry’s army left Southampton on 11 August, late in the season for a long campaign. It made for Harfleur on the River Seine, rather than English Calais, presumably “to stuff the town with Englishmen” so Normandy could be overawed, the channel secured and communications with Aquitaine established.

But the army found the town of Harfleur heavily fortified and the siege was long and disease-ridden; a third of the army either died or was invalided home with dysentery. The town eventually surrendered on 22 September after heavy bombardment. The decision to march through Normandy to Calais turned out to be dangerous. Henry’s exhausted army, perhaps 9,000 men, mostly archers, had difficulty in finding a safe crossing of the River Somme, so that instead of covering 150 miles, they marched 250 miles in 17 days, allowing a larger French army to overtake them. In the heat of battle at Agincourt, moreover, Henry flouted chivalric convention by slaughtering many captives. But his victory on 25 October swept all criticism aside.

To an English observer, the French seemed “like a countless swarm of locusts”, but they were not led by their king or his heir, and most of the royal dukes were absent. Henry donned his helmet with “a very rich crown of gold encircling it like an imperial crown” and delivered a speech to his men: “In the name of Almighty God, and of St George, Forward Banner! And St George this day thine help”. The French cavalry was dislocated by English and Welsh archers and the hand-to-hand fighting was ferocious. The French dead were piled to the height of a man’s head; the losses on the English side were astonishingly small. To the English, this seemed God’s work.

Agincourt was not a decisive battle, though Harfleur’s capture was important. For the French, the battle was devastating to morale. For the English, it became the stuff of patriotic propaganda focused on Henry V and binding nobles, churchmen and Parliament to his causes. He was reportedly carried ashore at Dover on the shoulders of exultant subjects; in London (23 November) pageants proclaimed: “Blessed is he who comes in the name of the Lord”. Agincourt helped to create a regal myth that sustained the king and his French enterprise − and made subsequent defeats seem all the more scandalous.

On the continent, the reputation of England and its king was transformed. At the Church Council at Constance (1414–18), English envoys lauded “our victorious king of England, Henry V, faithful soldier of Christ and strongest striver after peace”. Sigismund, Emperor of Germany, visited Henry (May 1416) to make peace between England and France, and went away his ally. In Italy the king was known as Il Magnifico. Agincourt’s memory spurred Henry to renew hostilities (1417) which led to the conquest of Normandy and the Treaty of Troyes (1420), which recognised him as heir to the French throne. 1415 was the year when the Lancastrian dynasty was stabilised at home and set out on extraordinarily ambitious paths abroad.

Key years: Other important events in the first half of the 15th century

1400 – Henry subdues the Scots. After seizing Richard II’s crown, Henry IV faced serious difficulties. A conspiracy to assassinate him at Windsor was thwarted at the last moment, and the nobles involved were killed at Cirencester (January). Richard II’s murder at Pontefract (February) outraged many; in the summer Henry led an army to subdue the Scots; and in September Owain Glyn Dwr declared himself prince of Wales, prompting Henry to lead his first expedition against the Welsh.

1401 – Licence to burn. The statute “on the burning of heretics” enabled the first English Lollard, William Sawtre, to be burned at Smithfield (March). It authorised relapsed heretics to be punished by a government that feared insurrection as well as criticism of the Church.

1403 – Battle of Shrewsbury. By quick and decisive action, Henry IV defeated Henry “Hotspur” and his father Northumberland, who had Welsh and Scottish support, at the Battle of Shrewsbury (July). This marked the beginning of the king’s long but successful campaign to quell rebellion against him.

1412 – First Scottish university founded. Scotland’s first university was founded at St Andrews and received authorisation from Pope Benedict XIII. Before that Scottish students went to continental (especially French) universities for their education and religious training during the wars with England.

1420 – Henry V becomes Duke of Normandy. The notable Treaty of Troyes between Henry V and Charles VI of France (May) was the pinnacle of Henry V’s achievement. It recognised him as duke of Normandy and heir to the French throne, and in June he married Charles’s daughter Catherine. The Dauphin was disinherited and Henry and Charles entered Paris together on 12 December. Henry V died two months before Charles VI (1422) so that the “dual kingdom” was inherited instead by the nine‑month-old Henry VI.

1429 – Right to vote is defined. A statute of the English Parliament defined the qualification for voting in county elections: it was limited to freeholders with property worth 40 shillings net per annum and was probably designed to raise the standing of MPs and avoid disputed elections. The statute remained in force until the Great Reform Act of 1832.

1437 – A great frost heralds high food prices. According to the Great Chronicle of London, early in the year there was “a passing great frost − and one of the strongest that hath been seen. For bread was frozen so hard together that unless men would thaw it by the fire men might not eat it nor cut it with a knife but if they would hew it with axe or hatchet”. There followed several years of grain shortage and high food prices in England and Scotland.

1440 – Eton and Cambridge are founded. Henry VI founded Eton College for 25 poor scholars, the first English king to found a public grammar school with educational and religious objectives. Four months later (February 1441) he also founded King’s College, Cambridge. They were among a number of such foundations in mid-15th-century England.

1449 – English power declines. Events in this year heralded a collapse of political confidence in England: an English attack on the Breton fortress of Fougères precipitated renewed war with France which soon ended the English occupation of Rouen (October) and Normandy. Meanwhile, the disgruntled Duke of York withdrew to Ireland (June) where he had a power-base, while James II strengthened Scotland’s alliances in the Low Countries by marrying Mary of Gueldres (July).

More turning points in British history

Read next: 1483: Richard grabs the throne

Go back: 1381: The Peasant's Revolt

Ralph A Griffiths is a historian and an emeritus professor at Swansea University

This article was first published in the December 2006 issue of BBC History Magazine