From ignorant Roman generals to over-ambitious American lieutenants, history is full of soldiers who made catastrophic mistakes. Conflicts as relevant as World War Two and as ancient as the Second Punic War were defined by these blunders and their consequences.
Some were caused by underestimating the enemy, others by failing to understand the battlefield terrain, but all brought disaster for these commanders and their men.
Here are ten of the worst mistakes in military history:
1. The Romans at the Battle of Cannae
In 216 BC Hannibal Barca famously crossed the Alps into Italy with only 40,000 soldiers. A vast Roman army of around 80,000 men was raised to oppose him, led by the two Roman consuls. At Cannae the majority of this huge force were lost owing to a disastrous error on the part of their Roman commanders.
The Roman generals’ plan at Cannae was to advance and punch through Hannibal’s thin battle-line, putting faith in their much larger infantry force. Hannibal, in contrast, had prepared a complex strategy.
He first ordered his infantry to feign withdrawals in the centre of his formation, drawing the eager Romans towards his crescent-shaped battle-line. The Romans, unsuspecting, thought they had the Carthaginians on the run and drove their forces deep into this crescent. Hannibal’s cavalry then drove off the horsemen who protected the Roman flank, and circled around the back of the huge Roman force, charging their rear.
The Roman commanders did not realise their mistake in time: the Carthaginian infantry’s crescent formation now surrounded them at the front, and Hannibal’s cavalry was driving into their rear. Roman soldiers were so tightly packed in this Carthaginian trap that they were unable even to swing their swords.
Around 60,000 Romans perished owing to their generals’ over-confidence, including Aemilius Paullus, one of the Roman consuls. It ranks alongside the the Battle of the Somme as one of the bloodiest days in western military history.
2. Crassus at the Battle of Carrhae
In 53 BC Marcus Licinius Crassus and his Roman legions were utterly crushed by the Parthians at the Battle of Carrhae. Crassus made the mistake of failing to recognise the importance of terrain and the skills of the Parthian horse-archers.
Crassus had marched 40,000 legionaries and auxiliary troops into the desert in pursuit of the Parthian army. He ignored the advice of his allies and advisers who had proposed staying in the mountains or near the Euphrates to reduce the danger from the Parthian cavalry.
Weakened by thirst and heat, the Romans were attacked by the Parthians deep in the desert. Misjudging the size of the Parthian army, Crassus ordered his men to form an immobile square which was devastated by the Parthian horse archers. When Crassus had his men pursue the enemy they were charged by cataphracts, the Parthian heavy cavalry.
Crassus’ many blunders resulted in his own death, and that of his son and 20,000 Roman soldiers. He also lost several Legionary Eagles, the Roman military standards, which were not recovered for over thirty years.
3. The Romans at the Teutoberg Forest
Across their long military history, few defeats left such an impact on the Romans as that of Varus’ legions at the Teutoberg Forest in 9 AD. On hearing news of the disaster, the Emperor Augustus famously cried aloud to himself repeatedly, ‘Quintilius Varus, give me back my legions!’.
Varus first made the error of trusting Arminius, a Germanian chieftain serving as his advisor. When Arminius informed him that a revolt had begun nearby, Varus marched his army through the Teutoberg Forest to deal with the problem.
Varus vastly underestimated the organisation of the Germanic tribes and their ability to use the local terrain; he did not reconnoitre the forest or even march his army in combat formation. As the Romans marched through the dense woodland, they were suddenly ambushed by a hidden and well-disciplined Germanic army led by Arminius himself.
Only a few thousand Romans escaped, and Varus himself was forced to commit suicide during the battle. Arminius’ victory prevented the Roman empire from ever establishing a firm grip on Germania.
4. The French at the Battle of Agincourt
On the morning of 25 October 1415, the French army at Agincourt would have been expecting a famous victory. Their army greatly outnumbered the English host under Henry V, and they had a much larger force of knights and men-at-arms.
The French, however, made a ruinous mistake, miscalculating the accuracy, range and firing rate of the English longbows. During the battle, the French cavalry attempted to charge the English archers, but were unable to pass the sharpened stakes which protected them. Meanwhile the French men-at-arms moved slowly over the muddy ground separating them from the English.
In these conditions, the entire French army was hugely vulnerable to the constant hail of arrows from the English longbows. The French were easily beaten back when they finally pushed through the arrows to Henry V’s lines. Their mistakes resulted in the French losing around ten times the number of English casualties.
5. The Austrians at the Battle of Karánsebes
On the night of 21-22 September 1788, during the Austro-Turkish War, the Austrian army under Emperor Joseph II defeated itself in a major friendly-fire incident.
Clashes between Austrian troops began when the Austrian Hussars who were serving as scouts refused to share their schnapps with some infantry. After one of the drunken Hussars fired a shot, the infantry opened fire in return. As the two groups fought, they heard shouts of ‘Turks! Turks!’, leading them to believe the Ottomans were nearby.
The Hussars fled back into the Austrian camp, and a confused officer ordered his artillery to fire upon them. In the darkness, the Austrians believed the Ottoman cavalry were attacking them unawares and turned on each other in terror.
Over 1,000 Austrians were killed during the night, and Joseph II ordered a general withdrawal on account of the chaos. When the Ottomans actually arrived two days later, they took Karánsebes without a fight.
6. Napoleon’s Invasion of Russia
The invasion force which Napoleon mustered for his campaign against Russia was the largest army ever assembled in the history of warfare. Over 685,000 men from France and Germany crossed the Neman River and began the invasion. After Napoleon’s failure to force the Russians to surrender and lengthy retreat, his army would suffer 500,000 casualties.
Napoleon falsely believed the Russians would deploy their army in a conclusive battle, but instead they withdrew deeper into Russian territory. As the Russians retreated they destroyed crops and villages, making it impossible for Napoleon to supply his huge host.
Napoleon managed to inflict an inconclusive defeat on the Russians and seize Moscow, but even the capital had been destroyed by the withdrawing army. After waiting in vain for Emperor Alexander I to surrender, Napoleon fell back from Moscow.
As winter approached, snows slowed the French army, who suffered from starvation and desertion as the Russians harried their long retreat.
7. The Charge of the Light Brigade
Immortalised by Alfred, Lord Tennyson’s poem, this British light cavalry charge during the Battle of Balaclava is one of the most renowned military mistakes in history. After a miscommunication in the chain of command, the Light Brigade was ordered on a frontal assault against a large Russian artillery battery.
As the Light Brigade charged between the Fedyukhin Heights and the Causeway Heights (the so-called ‘Valley of Death’), they faced devastating fire from three sides. They reached the artillery but were driven back, receiving more fire during their retreat.
In the end, the miscommunication caused nearly 300 casualties in a matter of minutes.
8. Custer at the Battle of the Little Bighorn
The Battle of the Little Bighorn is one of the most well-known engagements in America’s military history. For decades after the battle Lieutenant-Colonel George Custer was considered an American hero for his Last Stand against the forces of the Lakota, Northern Cheyenne and Arapaho Tribes.
Modern historians have documented Custer’s various mistakes before and during the battle, which led to a decisive victory for the tribal war leaders Crazy Horse and Chief Gall. Notably, Custer seriously misjudged the number of enemies camped before the Little Big Horn River, ignoring his Native scouts’ reports that the encampment was the largest they had ever seen.
Custer was also supposed to wait for Brigadier General Alfred Terry and Colonel John Gibson’s troops to arrive before launching an attack. Instead, Custer decided to make his move immediately, afraid that the Sioux and Cheyennes would escape if he waited.
Custer was forced to retreat his own battalion to a nearby hill, where they all perished facing repeated assaults.
9. Hitler’s Invasion of the Soviet Union
Operation Barbarossa, Hitler’s failed invasion of the Soviet Union in 1941, was one of the most significant military campaigns in history. Following the invasion, Germany was engaged in a war on two fronts which stretched their forces to breaking point.
Much like Napoleon before him, Hitler underestimated the resolve of the Russians and the difficulties of supplying his forces for the Russian terrain and weather. He believed that his army could seize Russia in only a few months, so his men were not prepared for a harsh Russian winter.
Following the German defeat in the largest battle in history at Stalingrad, Hitler was forced to redeploy troops from the western front to Russia, weakening his hold on Europe. The Axis Powers suffered nearly 1,000,000 casualties during the campaign, which proved a turning point in the Second World War.
10. The Japanese attack on Pearl Harbor
In the early hours of 7 December 1941 the Japanese launched a pre-emptive strike against the American naval base at Pearl Harbor. The Japanese intended the attack to be a preventative action, hoping to stop the American Pacific Fleet from halting Japanese expansion into Southeast Asia. Instead, the strike drove America to join the Allies and enter the Second World War.
Initially the Pearl Harbor attack, which coincided with other strikes on American naval bases, was a success for the Japanese. 2,400 American personnel were killed, four battleships were sank and many more suffered severe damage.
However, the Japanese failed to deliver a decisive blow, and American popular opinion turned from isolationism towards involvement in the war. Over the coming years America not only helped turn the tide of the conflict in Europe, but also ended the Japanese Empire in the Pacific.