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Death of a Kingdom III: Tarquin Is Defeated at Lake Regillus

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The author is a student of ancient and modern European history.

The last king of Rome depicted in a drawing

The last king of Rome depicted in a drawing

The Last King of Rome

Lucius Tarquinius Superbus was the last king of Rome before the rise of the republican government in the Latin system. Tarquin the Proud, as he came to be known, had a long list of accomplishments both on and off the battlefield. His building projects elevated the city of Rome and set its gods apart from their neighbors. His wars enriched the Roman nobility and gave Rome a firmly set warrior class. But all of Tarquin's accomplishments were tragically swept away in the republican furor that threw out monarchy in Rome.

Tarquin sought to rebuild and restructure Rome and firmly entrench himself in the city by doing so. His construction projects put a strain on the plebeians, forcing them to toil at his projects for many years. Meanwhile, he kept up a string of campaigns that brought his armies to the field of battle year after year. While he was successful, the patricians allowed Tarquin's dictatorial sense of entitlement. But when Tarquin failed to capture the cities of the Rutelli by force, opinions in Rome turned swiftly.

Tarquin was cast out of Rome, his throne seized and dismantled, and all of his immediate family cast down. Tarquin did not take these offenses lightly. At Silva Arsia, he led an army to a narrow defeat at the hands of the Romans and lost a son for it. At Clusium, Tarquin sought the help of his fellow Etruscans, but they too failed to retake his throne in the Roman-Clusium War. Now an old man, Tarquin was running out of options. But he found one last chance in his son-in-law, Octavius Mamilius.

Mamilius was a leading man in the Latin city of Tusculum, one of Rome's neighbors. He had married Tarquin's daughter and was an important ally of the former king of Rome. Mamilius was tied to Tarquin by blood and probably saw a chance to humble Rome, a city that had risen to prominence under Tarquin. Thus, Mamilius was made dictator of Tusculum. He raised an army of Latins and met the Roman army at Lake Regillus.

Lake Regillus

Lake Regillus

Dating Controversy

There is some debate among historians as to when the Battle of Lake Regillus actually took place. Many of the primary records of the early Roman Republic are lost to history. Many records were destroyed when the Gauls sacked Rome in 390 BC. But others were lost over the ages due to fires and poor record keeping. It is likely that leading Roman families throughout the ages destroyed, embellished, or modified records that did not suit their agenda as well.

Livy, working from primary sources lost to us, states that the battle took place in 499 BC, but that it could have been in 496 BC. Dionysius of Halicarnasus states that the battle took place in 496 BC. Regardless of the actual date of the battle, its effect on the Latin world cannot be denied.

Battle at Lake Regillus

Lake Regillus lay in a volcanic crater sitting between Rome and Tusculum. Aulus Postumius Albus, appointed dictator by the Roman Senate, led the Roman army. Octavius Mamilius, who was the dictator of Tusculum, led the Latin forces assembled against them. Tarquin the Proud was counted among the Latin forces, and his last surviving son, Titus Tarquinius, led a contingent of Roman exiles into the battle.

Like many of the republic's early battles, this was a closely contested fight where the tide of battle remained indecisive until the reserves were taken into the field. Servius Tullius, the sixth king of Rome, had introduced an expanded levy into the Roman army and is credited with reorganizing the army in the 550s BC. In this reformed army, the richest citizens, who could afford the best equipment, led the citizen infantry from the front. As they could afford heavy armor, shields, and spears, they presented a united front with the lower classes, bulking out the body of the infantry. By the Battle of Lake Regillus, this process was in flux. Nobles and those rich enough were consistently part of the cavalry, with the infantry being almost entirely comprised of the lower classes. Livy states that the battle was turned when the noble sons dismounted their cavalry and fought side by side with the lower classes as infantry.

Our sources show that in the early republic, nobles were almost always mounted. At Silva Arsia, consul Brutus fought Aruns Tarquinius on horseback, and both died from their wounds. Again at Lake Regillus, we see the combat opens with the noble cavalry from both sides engaging. Mamilius leads his bodyguard into combat with Titus Abutius Helva, the Roman Master of Horse, leading to both men being injured, though only Abutius was forced to retire. Postumius, the dictator, engages Tarquin the Proud, but the older Tarquin is injured and forced to retire. These few examples show the shift away from the ideal of nobility fighting as hoplites on foot in duels and moving toward mounted commanders that became more common in classical antiquity.



After the first mounted duels, the commanders had retired or returned to their lines and the infantry engaged. Titus Tarquinius, leading the Roman exiles, began to turn the Roman line. A former consul, Volesus, was killed by a spearman while trying to reach Titus, and the line began to crumble. Here, Livy records two events of interest to the reader. First, a duel breaks out between the advancing Latins and Romans. Titus Herminius Aquilinus rides at and engages the Latin dictator Octavius Mamilius. Mamilius is killed, and Herminius tries to loot his armor and gets impaled by a javelin. This is from where the Roman manipular system begins to evolve. These sorts of duels would be carried into the traditions of the velites as Rome moved toward the Triplex Acies.

Secondly, Livy notes that Postumius then brings his own forces into the battle. Sometimes these are described as the Lictors, but there would have only been two dozen men, hardly enough to turn the tide of battle—and certainly not able to spread out enough to strike down fleeing soldiers to restore order, as some accounts detail. It is much more likely that these special forces were clients of the gens Postumia, comprised of citizen and non-citizen soldiers loyal to the gens, rather than those who served as part of the levy of soldiers from Rome.

Postumius also calls on the nobles to dismount and join the rest of the infantry. With the death of the Latin dictator, the reserves brought by Postumia, and the united front of the Roman people, the Latin forces were driven from the field and their camp sacked. The Battle of Lake Regillus would be the last time Tarquin the Proud would take the field.


The defeat of the Latins and the death of his son-in-law was the last opportunity for Tarquin to rally allies. He'd lost his own power at Silva Arsia, his Etruscan allies had abandoned him as the Roman-Clusium War—and at Lake Regillus, the Latins were crushed and dispersed. Rome would stay a free republic, but surviving the wars initiated by Tarquin changed the Roman people. They had tasted success and war.

Further Reading

  • Armstrong, J. (2016). Early Roman warfare: From the regal period to the First Punic War. Barnsley, South Yorkshire: Pen & Sword Military.
  • DeVries, Kelly. Battles That Changed Warfare, 1457 B.C - 1991 A.D.: from Chariot Warfare to Stealth Bombers. New York: Metro Books, 2011.
  • Lendon, J. E. Soldiers & Ghosts: a History of Battle in Classical Antiquity. New Haven: Yale University Press, 2008.
  • Livy, and Betty Radice. Rome and Italy: Books I-V. Harmondsworth, Middlesex: Penguin Books, 1982.
  • Mackay, Christopher S. Ancient Rome: a Military and Political History. Cambridge: Cambridge University Press, 2007.
  • Penrose, Jane. Rome and Her Enemies: an Empire Created and Destroyed by War. Oxford: Osprey, 2005.

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.