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The Worst Military Defeats of Rome

Read on to learn about five of ancient Rome’s worst defeats in battle.

Read on to learn about five of ancient Rome’s worst defeats in battle.

What Were Rome’s Worst Defeats?

Rome was the most successful city-state in European history. Starting from humble backgrounds when they controlled not much more than their own city, with time, the people of the Eternal City expanded their influence to the point when they were able to call the Mediterranean Sea Mare Nostrum.

The military muscle of the legions was the force that allowed the people of Rome to conquer the territories that would later form the Roman Empire. Rome’s legions were undoubtedly one of the most successful and well-oiled military machines of human history, but they were far from unbeatable. During the expansion of their domains and later in the defence of their mighty empire, the eagles suffered many heavy defeats also.

These defeats rarely proved fatal for the Romans, as their grit, determination and ingenuity usually allowed them to turn around the situation and defeat or wear down their enemies.

In the following parts of this article, I will name some of the worst defeats suffered by Rome, explain how and why these defeats occurred, and discuss how (if this is the case) the Romans were able to overcome the short-term disaster and prevail over their enemies.

Worst Military Defeats of Rome

  1. Battle of Cannae
  2. Battle of Carrhae
  3. Battle of the Teutoburg Forest
  4. Battle of Edessa
  5. Battle of Adrianople

Battle of Cannae

The Battle of Cannae was one of the bloodiest and most costly battles of pre-industrial warfare in terms of loss of human life.

Two decades before the battle, the Romans defeated the Carthaginians and conquered Sicily from them. Many Carthaginians saw this defeat as a humiliation and were eager to get revenge on the Romans. One such figure was Hannibal Barca.

Hannibal conquered territory for Carthage in modern-day Spain, and the expansion of Hannibal drew the ire of the Roman Republic. When diplomacy failed, war broke out between Carthage and the Romans. Hannibal decided to take the fight to the Romans in Italy and invaded the peninsula through the Alps.

He defeated two Roman armies at the battles of Trebia and Lake Trasimene. The Romans were not deterred by their losses but gathered an even bigger army, some 86,000 strong if the ancient sources are correct, and marched against Hannibal. Hannibal only had some 50,000 soldiers at his disposal, but his cavalry was superior to that of the Romans. Using the deep concentration of the Roman infantry, Hannibals succeeded in negating his numerical disadvantage and encircled the Roman army, which turned the battle into a massacre.

The Romans lost some 67,000 men (killed, wounded and captured), and upon receiving the news of the battle, some of Rome’s Italian allies defected. Nonetheless, as Hannibal did not march on the virtually undefended city, the Romans decided to continue the fight. Their new commander Fabius refused to fight more large-scale pitched battles but targeted Hannibal’s supply lines and attacked Hannibal’s allies.

The strategy worked well, and after some years of conflict, Scipio landed and conquered Spain. Scipio later attacked North Africa and defeated Hannibal at the Battle of Zama, ending the Second Punic War.

Battle of Carrhae

Carrhea is another famous defeat of Roman arms; though, unlike Cannae, this battle did not pose an existential threat to the Republic.

By the time of Carrhae, the Republic was in terminal decline, and rich aristocrats were turning the armies and institutions of the Republic into their private forces. During the 50 BCs, the Republic was dominated by three figures: Pompey the Great, Marcus Crassus and Julius Caesar. Caesar and Pompey were accomplished military leaders. Crassus also participated in campaigns during his younger years, but by 55 BC, he was thoroughly in the shadow of his colleagues regarding military achievements.

Jealous of his allies, Crassus got himself the governorship of Roman Syria. Using his position and personal wealth, Crassus assembled an army of around 40,000 and invaded the Parthian Empire. The King of Armenia offered to ally himself with Crassus and unite their two armies if Crassus agreed to attack Parthia through Armenia.

Crassus declined the offer and rather attacked the Parthians through Mesopotamia. This allowed the King of Parthia to divide his armies and deal with the dangers separately. The King led his troops in person and defeated the Armenians, while he delegated command against the Romans to a noble from the House of Suren.

The force sent against the Romans was entirely mounted (9,000 horse archers and 1,000 heavy cavalries). The Romans lacked the cavalry and missile troops to deal with this cavalry army, and when the two armies collided, the Parthians wore down the Romans, who were saved by nightfall, which allowed the survivors to retreat.

Crassus was pressured into a parley by his troops, but he was killed during the meeting. The manner of Crassus’s death is unclear, with one version claiming that the Parthians poured melted gold down his throat to mock his greed.

The surviving Romans were led back to Syria by Gaius Cassius, but the defeat was a great embarrassment for the proud Romans. Mark Antony led an invasion to avenge the defeat of Crassus, but he fared little better than Crassus, as thanks to supply problems, he was forced to retreat after sustaining heavy losses.

Battle of the Teutoburg Forest

After defeating Mark Antony and Cleopatra, Octavian, the later Emperor Augustus, began to greatly expand the Roman Empire. He annexed Egypt and several other client kingdoms to Rome. His expansion was not limited to the Middle East, as under his rule, the Eagles crossed the Rhine, and Roman rule was spread as far east as the Elbe.

Despite the outward appearance of successful conquests, in reality, the Germanic tribes were far from defeated just yet, and the situation was rather volatile. The commander and heir of Augustus, Tiberius, was not convinced the areas were worth the trouble of the conquest, as the region between the Rhine and Elbe was heavily forested and quite impoverished. Nonetheless, under his command, the Germanic tribes were kept under control.

Things changed when Tiberius was forced to leave Germania to quell a revolt in Illyria. He was succeeded by a man named Quintilius Varus. Varus was an experienced man who served the Emperor well in Syria and North Africa. He was a capable administrator but not a military man of the stature of Tiberius.

A Germanic chieftain Arminius saw the departure of Tiberius as the moment to regain his independence. He succeeded in rallying some tribes to his cause, though by no means all of them. Arminius spent his youth as a hostage in Rome and knew the Roman army and its strengths and weaknesses well.

Outwardly he appeared loyal and very helpful and easily gained the trust of Varus. Such was the trust of Varus that the governor refused to believe a fellow Germanic chieftain who gave away Arminius’s plans to him.

Varus’s trusts were to cost him dearly soon after, as Arminius led him straight into an ambush, where three Roman legions and their allies were slaughtered in the Teutoburg forest.

The news of Varus’s death and the destruction of the legions shocked Emperor Augustus, who supposedly beat his head into the wall and cried out: “Quintilius Varus gave me back my legions!”

The Romans sent several putative expeditions to punish the Germanic tribes, and Germanicus campaigned in Germania for years. Nonetheless, eventually, the Romans abandoned the province and set up their frontier at the Rhine rather than the Elbe.

Battle of Edessa

The Battle of Edessa was probably much closer to Cannae than Carrhae or the Battle of the Teutoburg forest were, as despite the great losses sustained in these latter two battles, neither really served as an existential threat to the Romans.

The Third Century was a very turbulent one from the perspective of the Roman Empire. After the assassination of Emperor Severus Alexander, soldier emperors quickly followed each other on the throne, usually meeting their end by the blades of their own soldiers.

While civil war was tearing apart the empire, a new dangerous enemy emerged in the east, the Sassanid Empire. Led by Shah Ardashir and later his son Shapur, the Persians created havoc in the Eastern provinces of Rome.

To deal with Shapur’s problems, Emperor Valerian led a large army to Syria. Little is known about the Battle of Edessa; however, the outcome is well known. The Romans suffered a devastating defeat, and even the Emperor was captured. Shapur overran much of the Roman east in the aftermath of his victory, and it was not the son of Valerian, Emperor Gallienus, but a Palmyrene nobleman named Odaenathus who succeeded in stabilizing the situation in the east.

Odaenathus remained loyal to Rome, though he ruled the Roman East like an independent monarch. After his assassination, his wife Zenobia seceded from Rome. It was not until the arrival of Emperor Aurelian and his veteran legions that Syria and Egypt were brought back under the empire’s control.

Battle of Adrianople

Some historians see Adrianople as the moment when the decline of the empire became irreversible. Previously to the Battle of Adrianople, many alien tribes were allowed to settle inside the Roman Empire; however, these were usually broken up and, with time, assimilated into the empire’s population. This status quo ended with the settlement of the Goths in the Balkans in 382.

The seeds for Adrianople were planted two years before the battle, in 376. Fleeing the arrival of the nomadic Huns, a large number of Gothic tribesmen (according to some historians, as many as 200,000 with families included) asked for asylum in the empire at the Danube.

While the Goths were at the Danube, Emperor Valens fought against the Sassanids in the east. Half the Goths were allowed to enter the empire; however, by their cupidity and incompetence, the Roman authorities soon turned the Goths against them, who started ravaging the Balkans’ countryside. The local Roman forces were defeated, and the rest had to retreat to the fortified towns or block mountain passes.

The Emperor asked for reinforcements from his nephew Gratian, the Western Emperor. Gratian complied, but even the reinforcements were not enough to destroy the Goths.

Valens made peace in the east and returned to the Balkans in 378. He brought with him whatever troops he could from the east, but it is believed that his army was no bigger than 15,000-20,000 soldiers. He also asked his nephew Gratian to join him and destroy the Goths with their combined force; however, Gratian was forced to remain in the Rhine region longer thanks to Germanic attacks on that frontier. Nonetheless, once the situation on the Rhine was stabilized, Gratian marched east and urged his uncle to wait for his arrival.

Valens marched out alone to fight the Goths before Gratian was able to arrive. Historians believe that the main reasons for Valens’s decision were faulty intelligence (he believed the Gothic army was smaller than what it was) and a certain level of envy towards his nephew’s military victories.

Whatever his motives, Valens marched out alone to fight the Goths. The Gothic leader Fritigern invited Valens to a parley, but as the sides talked, part of the Roman cavalry charged without orders, only to be beaten back. The battle began before the Romans deployed in their battle formations, and by this, they squandered whatever advantage they may have had thanks to their training and discipline. The battle was decided by the returning Gothic cavalry (who were not present at the beginning), the cavalry charged the disorganized Romans, and the battle turned into a massacre, which not even Emperor Valens could escape alive.

Gratian elevated a trusted general named Theodosius to become the new Eastern Emperor; however, despite his best efforts and four years of hard campaigning, Theodosius also failed to destroy the Goths and had to make an accommodation with them in 382.

For the first time in their history, the Romans allowed outsiders to make settlements inside the empire and remain under the control of their own chiefs. The example of the Goths later was followed by many more barbarian groups, who, in the end, carved up the Western Roman Empire among themselves. However, the East managed to survive for another 1000 years, though it has to be said, from the middle of the 7th century, in a much, much-diminished form.


Heather. Peter. (2005). The Fall of Rome: A New History. Oxford UP.

Holland, Tom. (2005). Rubicon: The Last Years of the Roman Republic. Anchor.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.