Lessons of hostory ignored, as usual

The Black Sea Fleet's progressive destruction since 2022 — examined in detail elsewhere in this series — has prompted a question that keeps recurring in defence analysis: why do capable military forces, confronted with evidence that their tactical assumptions are wrong, continue on the same trajectory until the losses become unsustainable? The Russian Navy faced the Neptune anti-ship missile, the Magura V5 unmanned surface vessel, and the Sub Sea Baby underwater drone in succession. Each system demonstrated that existing Russian countermeasures were inadequate. The institutional response was to add boom defences and helicopter patrols rather than to fundamentally reassess.

The French army at Agincourt in 1415 had faced the English longbow at Crécy in 1346 and at Poitiers in 1356. The institutional response was to add armour and more men. On 25 October 1415, on a narrow muddy field in northern France, the consequences of that failure to adapt became irrevocable.

Agincourt repays modern operational analysis not as colourful historical background but as a case study in exactly the failure modes that produce military catastrophe: terrain misread, command dysfunction, technology underestimated, and an enemy consistently undervalued until undervaluing him was no longer possible. The rhyme across six centuries is audible. What follows is an attempt to make it precise.

The Ground

Six hundred and eleven years have not substantially altered the essentials of the Agincourt battlefield. The field between the villages of Agincourt and Tramecourt in the Pas-de-Calais remains what it was on 25th October 1415: a narrow corridor of open ground flanked by dense woodland, running roughly north to south, approximately 900 metres wide at the point where the two armies faced each other. A modern staff officer examining the site would recognise it immediately for what it is — a killing ground with no room for manoeuvre on either flank.

Heavy rain in the days before the battle had reduced the recently ploughed field between the armies to glutinous clay. A defending force with the woods at its back would be on firmer going than an attacking force crossing the open ground. These were not accidental advantages. Henry V had chosen his position with care, and the choice tells us a great deal about his understanding of the battle he intended to fight.

In modern operational terms, Henry had identified and exploited the terrain to create a classic area-denial problem for his opponent. The woodland constrained the French frontage — a force that outnumbered his by at minimum three to one, and possibly as much as six to one, could not bring its numerical advantage to bear. The mud degraded the mobility of the heaviest elements of the French force — the armoured men-at-arms and cavalry — while leaving the lightly equipped English archers, on firmer ground behind their defensive stakes, relatively unimpaired. Before a single arrow was loosed, Henry had chosen a battlefield that neutralised the primary French advantage and amplified his own.

Intelligence and Situational Awareness

The English picture

Henry's intelligence picture on the eve of battle was better than is sometimes credited. The march from Harfleur to Calais — some 260 miles through French-controlled territory — had provided continuous contact reconnaissance. French forces had been shadowing the English column for days, and the English knew it. Heralds had passed between the armies; the broad dispositions of the French force were not unknown to Henry. He understood that he was facing a substantially larger army, that it included heavy cavalry and dismounted men-at-arms in large numbers, and that the French were confident of victory.

What Henry also understood — and this is the intelligence assessment that shaped his tactical decision — was French intent. The French high command fully intended to attack. They were not going to wait and starve him out, though the wiser heads among them advocated precisely that course. Henry gambled that French impatience and overconfidence would drive them onto his prepared ground. He was right. The provocation of advancing the English line to reduce the killing distance — to a range at which his archers could open fire effectively and draw the French forward — was a deliberate operational choice, not a defensive reaction.

The French picture

The French intelligence picture was, by contrast, fragmentary and distorted by institutional bias. The fundamental failure was not a lack of information about English positions — those were visible enough — but a comprehensive misreading of English capability and intent. The French high command had absorbed the same lesson from Crécy (1346) and Poitiers (1356) that the Black Sea Fleet would absorb from Moskva's sinking six centuries later: the lesson that last time was an aberration, that the fundamental equations of military power had not actually changed, and that a sufficiently large force of properly equipped men would overwhelm what had previously proved unexpectedly dangerous.

French commanders knew the English had longbowmen. They had faced them twice before and lost twice before. The institutional response was to add more armour and commit more men, rather than to develop a tactical answer to the weapon itself. It was the medieval equivalent of building bigger surface combatants to counter a threat that required a different kind of thinking entirely.

There was a further intelligence failure of a kind familiar to any student of command dysfunction: the subordination of professional military judgement to social and political pressure. The Constable of France, Charles d'Albret, and Marshal Boucicault were experienced commanders who both correctly assessed that the right course was to surround and starve the English into surrender. Henry's supply situation was genuinely precarious; given time, the campaign might have ended without battle. D'Albret and Boucicault were overruled by the assembled nobility of France, who had not come to watch and wait. The result was that the French army's operational plan was determined not by its professional military leadership but by the social dynamics of its feudal command structure — a distinction with consequences that the field made brutally clear.

Command and Control

Henry V

Henry's command arrangements were compact, clear and personally anchored. He commanded from the front — not in the modern sense of forward leadership for morale purposes alone, but in the medieval sense that the commander's physical presence was the command system. There was no intermediate headquarters, no staff layer between intention and execution. Orders were simple: hold the line, anchor on the stakes, loose when the range closes, close with whatever reaches you.

Critically, Henry had unified command. Every English soldier at Agincourt answered to a single authority whose intent was unambiguous and whose presence was visible. When a reported attack on the English baggage train during the battle prompted Henry's controversial order to kill the French prisoners being held behind the English line — an order that has exercised historians and lawyers ever since — it was issued and executed without hesitation or internal debate. Whether or not the order was militarily justified or morally defensible, the command system that produced it was functional.

Henry also managed morale with something approaching genius. The army that faced the French at Agincourt was exhausted, depleted by dysentery from the Harfleur siege, and had been marching for over a fortnight through hostile territory. Desertion would have been rational. That it did not occur on any significant scale reflects a level of command authority and troop cohesion that cannot be explained by discipline alone. The St Crispin's Day speech, whatever Shakespeare made of it, reflects a genuine historical reality: Henry worked his men hard on the night before battle, moving among them, visible, confident, purposeful. In modern terms, he managed the information environment inside his own force with as much care as he managed the tactical plan.

The French command: a case study in dysfunction

The French command arrangement at Agincourt was, by any measure, a structural failure waiting to become a catastrophic one. The nominal supreme commander, King Charles VI, was absent — incapacitated by the episodes of psychotic illness that had plagued his reign, earning him the historical epithet Charles the Mad. Command devolved to d'Albret as Constable of France and Boucicault as Marshal — professional soldiers of genuine competence, but without the social rank to impose their will on an army whose most powerful elements outranked them.

The French force was organised into three divisions — vanguard, main battle, and rearguard — a conventional medieval disposition that made operational sense on open ground and almost none in the confined corridor at Agincourt. The vanguard and main battle were so closely packed that when the vanguard stalled in the mud under arrow fire, the main battle compressed into it from behind, converting two divisions into a single incoherent mass. The rearguard, which might have been used to turn a flank or find a route through the woods, was never meaningfully committed. It stood, watched, and retreated.

There was no mechanism for the French commanders to impose tactical adjustments once the advance began. The army's command architecture — built around the social precedence of individual nobles commanding their own retinues — had no equivalent of a staff system capable of reading the battle and redirecting forces. When d'Albret was killed early in the fighting, the army continued on its existing trajectory because there was no alternative command node capable of redirecting it. In modern terms, the French had a single point of failure at the command level and no redundancy. The English had neither problem.

Morale and Force Cohesion

The morale asymmetry at Agincourt deserves more analytical attention than it typically receives, because it ran counter to what the material circumstances appeared to predict.

The English force was in objectively poor condition. Weeks of marching, inadequate supply, significant sickness, and the knowledge of being vastly outnumbered on enemy territory were not conditions calculated to produce a confident fighting force. What they produced instead was a force stripped of options and therefore of anxiety about choices: there was nowhere to go, no realistic prospect of negotiated extraction, and a commander who communicated clearly that standing and fighting was both the only course and a course that would succeed. Soldiers who understand their situation, however dangerous, and trust their command are more functional than soldiers whose situation appears better but whose command gives them reason to doubt.

The French morale picture was precisely inverted. An army that had assembled in the expectation of easy victory, packed so tightly that individual fighting effectiveness was degraded before contact, watching the men ahead of them fall and pile up, with no room to manoeuvre and no coherent order coming from above — that army's will collapsed with a speed that shocked even its opponents. The French second and third lines, which never properly engaged, dispersed when the scale of the vanguard's destruction became clear. The social glue of feudal military service — the obligation to follow one's lord into battle — failed when the lord himself was gone and the battle was visibly lost.

Technology and Tactical Innovation

The longbow: what it actually did

The English longbow has acquired a legendary status that has, paradoxically, obscured what made it operationally decisive at Agincourt. It was not simply a powerful weapon. Powerful weapons had existed before. What made the longbow decisive on this particular field was the combination of rate of fire, range, and the specific vulnerability it exploited in the French tactical system.

A trained English or Welsh longbowman — and training was generational, beginning in childhood, producing the skeletal deformities that modern archaeology has confirmed in remains from the period — could loose ten to twelve aimed arrows per minute. With approximately five thousand archers on the English line, the French advance walked into what modern analysts would recognise as a suppressive fire problem: the volume of incoming projectiles was sufficient to disrupt organised movement regardless of individual lethality. Arrows that did not penetrate armour still injured horses, drove men to seek cover, broke formation, and generated noise and confusion that degraded command.

John Keegan's insight, in his landmark 1976 work The Face of Battle, remains the most useful modern framing: the longbow's decisive effect on the cavalry charge was primarily through the horses. Horses at Agincourt were armoured only on the head; arrows into flanks, rumps and legs produced animals in uncontrolled panic galloping back through the advancing French infantry. The churned mud already slowing the infantry became more churned. The packed ranks became more packed. The killing zone ahead of the English line became a compression problem for which the French tactical system had no answer.

The sharpened stakes driven into the ground at an angle by the English archers represented a tactical innovation not seen at Crécy or Poitiers. They converted the archer position from a firing line into a defensive work — a medieval anti-cavalry obstacle that forced horsemen to seek gaps, funnel into concentrated fire, or pull up short. The stakes cost nothing, required no logistical tail, and could be carried in the hand. They were, in modern terms, a force multiplier requiring no supply chain. The simplicity of the solution, against a threat that had been consistently underestimated, is its own commentary on the relationship between resource constraints and tactical creativity.

The historiographical debate

It is worth noting that the traditional account of Agincourt — outnumbered perhaps six to one, the English bowmen win an impossible victory — has been substantially revised by modern scholarship. Professor Anne Curry's work, drawing on contemporary muster rolls and tax records rather than chronicle sources, suggests that the French numerical advantage may have been considerably smaller than the traditional figures imply: perhaps twelve to fifteen thousand French against eight to nine thousand English, rather than the thirty-thousand-plus figures from medieval chronicles. If Curry's analysis is accepted, Agincourt becomes a less miraculous and more explicable event — a victory of tactical skill, terrain selection and command coherence over numerical superiority, rather than an almost supernatural triumph against overwhelming odds.

The revision matters for what Agincourt teaches. If the English were never as outnumbered as tradition holds, the lesson is less about the power of the longbow per se and more about the power of preparation, terrain exploitation, unified command and the tactical use of a weapons system the opponent had consistently failed to develop an adequate counter to. Those are, if anything, more useful lessons than the miraculous ones.

The French Perspective: What Went Wrong

French accounts of Agincourt — and there are several, including the account of the monk of Saint-Denis who provides some of the most vivid contemporary detail — carry a quality of stunned incomprehension that itself tells us something important. The French did not believe, going into the battle, that what happened was possible. The aftermath was therefore processed not as a failure of tactics or command but as a kind of cosmic injustice — God's inexplicable favour to the English, the treachery of fate. This is not simply medieval piety. It is the characteristic response of an institutional culture that cannot incorporate unwelcome evidence about its own limitations.

The losses sustained were catastrophic for French noble society. Among those killed were the Constable d'Albret himself, three dukes, five counts, and approximately ninety lords of lesser rank. The flower of French nobility, in the phrase that chroniclers used then and historians have used since, lay dead on a field in Artois. Perhaps six thousand fighting men were killed; another fifteen hundred nobles were taken prisoner, their ransoms eventually enriching English captors.

The political consequences were severe and prolonged. The Armagnac faction that had dominated the French court and committed its forces so disastrously at Agincourt was fatally weakened. The Burgundians, who had largely absented themselves from the battle, capitalised. The factional conflict that followed contributed directly to the conditions that produced the Treaty of Troyes in 1420, under which Henry V was nominated heir to the French throne — the maximum war aim he could conceivably have entertained when he crossed the Channel in 1415. A battle fought on a narrow muddy field in northern France reshaped the political geography of western Europe for a generation.

From the French perspective, the lesson that should have been drawn — that a feudal command system incapable of imposing professional military judgement on social hierarchy would fail against a more coherent opponent — was not drawn. The French army that Joan of Arc would lead to victory in the following decade operated on fundamentally different motivational principles, but the structural problems of French command persisted well into the following century. Institutional learning, in military affairs as elsewhere, is slow.

The Modern Lens: What Agincourt Still Teaches

The temptation, in applying modern operational analysis to medieval battles, is to find what one is looking for — to project contemporary frameworks onto events that may or may not support them. Agincourt is resistant to that temptation because the parallels are so direct that they require no projection.

Terrain exploitation as a force multiplier. The deliberate selection of a battlefield that neutralised numerical superiority and amplified defensive capability is a principle that requires no translation. Henry did at Agincourt what competent commanders have done before and since: he chose to fight where his strengths were advantages and his opponent's strengths were liabilities.

Command coherence versus command dysfunction. The contrast between a unified command with clear intent and a committee of nobles whose social dynamics overrode professional military judgement is not a medieval peculiarity. It is a recurring pathology, visible in military failures across every era. The Black Sea Fleet's institutional inability to report failure honestly upward, and its consequent inability to adapt, rhymes with d'Albret's inability to impose the correct operational decision on an army that outranked him.

Technological overmatch and the failure to adapt. The French faced the longbow at Crécy in 1346, at Poitiers in 1356, and at Agincourt in 1415. Each time they added armour and more men. Each time the result was the same. The lesson — that a weapons system which has demonstrated consistent lethality against your force requires a tactical counter, not more of what has already failed — was not learned in seventy years of painful experience. It is not obvious that modern military institutions learn faster.

Cost asymmetry and mass effect. Arrows were cheap. Trained longbowmen were not cheap — the investment in training was generational — but once trained, their output was extraordinary relative to cost. The mathematical relationship between the cost of the arrow and the cost of the armoured knight it disabled or killed prefigures, in its basic structure, the relationship between the Magura V5 and the vessels it has sunk in the Black Sea. The arithmetic of cost-effective attrition is not a modern discovery.

The prisoner killing. Henry's order to execute the French prisoners remains the most morally contested decision of the battle and the one most resistant to clean modern analogies. The operational logic was coherent — a renewed French attack while large numbers of armed prisoners were held behind the English line created a genuine tactical risk — but the act violated the laws of chivalric warfare as understood by contemporaries, and several English knights refused to carry it out. The tension between military necessity and the laws governing armed conflict was not invented in the twentieth century. Agincourt is one of its earlier and most starkly documented manifestations.

What Agincourt ultimately offers the modern military analyst is not a template but a mirror. The questions it poses — about command, about institutional learning, about the relationship between technology and tactics, about the psychology of forces in extremis — are the same questions that every conflict poses. The answers change with the weapons and the terrain. The questions do not.

The rhyme is audible across six centuries. It is not always comfortable listening.

A Note on Sources and the Historiographical Debate

The principal modern scholarly works consulted for this analysis are: John Keegan, The Face of Battle (1976), whose account of the longbow's physical effect on horses and men remains the most rigorous operational analysis of the engagement; Anne Curry, Agincourt: A New History (2005), whose reassessment of the force ratios based on primary muster records has substantially revised the traditional account; Juliet Barker, Agincourt: The King, the Campaign, the Battle (2005), which provides the most comprehensive treatment of the campaign context; and Clifford J. Rogers, 'The Hundred Years War' in various collected volumes, for the strategic framing. Contemporary sources consulted include the Gesta Henrici Quinti (Deeds of Henry V), the account of the Monk of Saint-Denis, and the chronicles of Jean de Wavrin. The question of the battlefield's precise location has been further complicated by Timothy Sutherland's archaeological work suggesting the designated site may not be the actual site — an uncertainty that does not affect the operational analysis but is noted for completeness.