Trajan’s Dacian Wars: Stretching the Borders of the Roman Empire

Welcome to Rome Across Europe!

If there’s something that can get us going it’s warfare. Military campaigns are what made Rome and, eventually, the Roman Empire.

Most of Rome’s greatest Generals and Emperors are remembered by history due to their success on the battlefield. This leads us to today’s adventure.

Following the Viae (Roman Roads) laid down by troops on the move, today we venture to join Trajan’s Dacian Wars!

Fiery battle scene between the Romans and Dacians (detail from Trajan’s Column).

Not to be confused with Domitian’s Dacian War (86–87 AD), the focus of these 2 military campaigns (101–102, 105–106) were during the rule of Emperor Trajan. Just like the earlier war under Domitian, the wars under Trajan were between Rome and Dacia.

The focus of Trajan’s conflicts were the constant Dacian threat on the Provincia (Roman Province) of Moesia. Just in case Trajan needed another reason to fight the Dacians, he could justify the war by saying a Roman victory would increase resources and the economy of the Roman Empire (which Rome was in desperate need of).

Since the reign of Burebista, widely considered to be the greatest Dacian king (82–44 BC) the Dacians had represented a threat for the Roman Empire. Julius Caesar himself had even drawn up a plan to launch a campaign against Dacia.

Panorama of the site on which the Battle of Histria took place.

An area north of Macedonia and Greece and east of the Danube, Dacia had been on the Roman agenda since before the days of Caesar when they defeated the Exercitus Romanus (Roman Army) at the Battle of Histria. The threat was reduced when dynastic struggles in Dacia led to a division into 4 or 5 independently governed tribal states after Burebista’s death in 44 BC.

Augustus later came into conflict with Dacia after they sent envoys offering their support against Mark Antony in exchange for requests, the nature of which have not been recorded. Augustus rejected the offer and Dacia put in their lot with Antony.

In 29 BC, Augustus sent several punitive expeditions into Dacia led by Marcus Licinius Crassus Dives (grandson of the famed Marcus Licinius Crassus who put down the Spartacus slave rebellion and of the First Triumvirate with Julius Caesar and Gnaeus Pompey) that inflicted heavy casualties and apparently killed 3 of their 5 kings. Although Dacian raids into Pannonia and Moesia continued for several years despite the defeat, the threat of Dacia had effectively ended.

Then, after 116 years of relative peace along the Roman frontier, in the winter of 85 AD to 86 AD the army of King Duras led by general Diurpaneus swarmed over the Danube the Roman Province of Moesia. Former Consul and present Roman Governor of Moesia, Oppius Sabinus, was killed during the attack.

Outline of the Roman Empire with the Provinces of Moesia Inferior (right) and Moesia Superior (left) highlighted.

The Dacians pillaged Moesia and initially defeated the Roman forces that Emperor Domitian sent against them. Emperor Domitian then led Legions into the ravaged province and reorganized the possession into Moesia Inferior and Moesia Superior, planning an attack into Dacia for the next campaign season.

With the arrival of fresh Legions in 87 AD, Domitian began what became the First Dacian War. General Diurpaneus sent an envoy to Domitian offering peace.

Romans don’t take too kindly to their countrymen being mistreated by foreigners, so that Dacian envoy sent requesting peace was immediately rejected on all grounds. He was probably lucky to leave Domitian’s alive.

Romans building a bridge on boats over the Danube.

The Praefectus Praetorio (Praetorian Prefect) Cornelius Fuscus hurriedly built a bridge on boats and rushed across the Danube into Dacia with 5 or 6 Legions. The Roman Army was ambushed and defeated at the First Battle of Tapae by Diurpaneus who was later renamed Decebalus (Dacian for “the Brave”) and who, as a consequence, was chosen to be the new king.

Fuscus was killed and the Legions lost their Aquilae (Eagle Standards), adding to the humiliation. However, in AD 88 the Roman offensive once more continued.

The Roman Army, this time under the command of Tettius Julianus, defeated the Dacians at the outlying Dacian fortress of Sarmizegetusa and at Tapae, near the current village of Bucova. After this defeat at the Battle of Tapae in AD 88, king Decebalus asked Domitian again for peace and was again refused.

Domitian’s Dacian War

Throughout most of the 1st Century AD, Roman policy dictated that threats from neighboring nations and provinces were to be contained promptly. The peace treaty following the First Battle of Tapae, followed by an indecisive and costly Roman victory on the same ground a year later, was unfavorable for the Empire.

Later Domitian accepted the offer, which led to the establishment of a truce between the Roman Republic and Dacia. This change of heart has been thought to be due to his Legions being needed along the Rhine to put down the revolt of Lucius Antonius Saturninus, the Roman Governor of Germania Superior who had allied with the MarcomanniQuadi and Yazgulyams against Domitian.

Statue of Decebalus (Deva, Romania).

Following the peace of 89 AD, Decebalus became a client of Rome, with acceptance of Decebalus as king (Rex Amicas). He received a lump sum of money, annual financial stipends, and craftsmen in trades devoted to both peace and war, and war machines to defend the Empire’s borders.

The craftsmen were used by the Dacians to upgrade their own defenses, while Decebalus continued to quietly oppose Rome. Some historians believe this was an unfavorable peace and that it might have led to Domitian’s assassination in September 96 AD.

Rome had been suffering economic difficulties largely brought on by military campaigns throughout Europe and in part due to a low gold content in Roman money as directed by Emperor Nero. Confirmed rumors of Dacian gold and other valuable trade resources inflamed the conflict, as did the Dacian’s defiant behavior, as they were “bowed and unbroken”.

Carpatian gold mines

Researchers estimate that Dacia had rich resources of iron and copper, and were prolific metal workers. A large percentage of the general Dacian population, not just the nobility like in Hispania and Gallia, owned swords.

This turn of events greatly reduced Rome’s military advantage over the Dacians. On top of that, Dacia sported 250,000 potential combatants or enough force to possibly invade Rome itself.

Dacia was allied to several of its neighbors and on friendly terms with others that Rome considered enemies. Rome had no concrete defense policy and would not have been able to sustain a war of defense.

Statue of Trajan carved from Luna and Proconessian marble in 2nd Century AD (Ostia Museum).

As such, the new Emperor Trajan, himself an experienced soldier and tactician, began preparing for war. He recommenced hostilities commence against Dacia, and even went so far as to withdraw troops from other borders leaving them dangerously undermanned.

After gaining the Senate’s blessing for war, by 101 Trajan was ready to advance on Dacia. This was a war in which the Roman military’s ingenuity and engineering were well demonstrated.

The Roman offensive was spearheaded by 2 columns of Legions, marching straight to the heart of Dacia, burning towns and villages en route. Following an uncertain number of battles, the Romans under Trajan defeated the Dacian king Decebalus in the Second Battle of Tapae in 101 AD.

With Trajan’s troops pressing towards the Dacian capital Sarmizegetusa Regia, in 102 AD Decebalus once more sought terms with Rome. The war had concluded with an important Roman victory.

Ruins of Trajan’s Bridge

A bridge, later known as Trajan’s Bridge, was constructed across the Danube at Drobeta to assist with the Legionaries’ advance. This bridge, probably the biggest at that time and for centuries to come, was designed by Apollodorus of Damascus and was meant to help the Roman Army advance faster in Dacia since the peace was actually lost by the Roman Empire.

According to the peace terms, Decebalus got technical and military reinforcement from the Romans in order to create a powerful allied zone against the dangerous possible expeditions from the northern and eastern territories by hostile migrating peoples. The resources were instead once again used to rebuild Dacian fortresses and strengthen their military.

Roman soldiers defending a fort against attack by the Dacians (detail from Trajan’s Column).

Following the first war, Decebalus complied with Rome for a time, but was soon inciting revolt among tribes against them and pillaging Roman colonies across the Danube. Soon thereafter Decebalus turned against the Romans once again and attacked Roman Castra (Fort) again in AD 105.

True to his intrepid and optimistic nature, Trajan rallied his forces in AD 105 for another war. Like the initial conflict, the next war involved several skirmishes that proved costly to the Roman military.

Faced with large numbers of allied tribes, Rome’s Legions struggled to attain a decisive victory resulting in a new temporary peace. In response Trajan again marched into Dacia, besieging the Dacian capital in the Siege of Sarmizegetusa, and annihilating it in the summer of AD 106 with the participation of the Legio II Adiutrix and Legio IV Flavia Felix and a detachment (vexillatio) from Legio VI Ferrata.

Decebalus fled, but was followed by the Equites Romani (Roman Cavalry) and committed suicide rather than submit. Thanks to the treason of a confidant of the Dacian king, Bicilis, the Romans found Decebalus’s treasure in the river of Sargesia/Sargetia (a fortune estimated at 364,865 lbs of gold and 729,730 lbs of silver).

The conclusion of the Dacian Wars marked a triumph for Rome and its Armies. Trajan announced 123 days of celebrations throughout the Empire.

Denarius issued by Trajan to celebrate the winning of the Dacian Wars.

Dacia’s rich gold mines were secured and it is estimated that Dacia then contributed 700 million Denarii per annum to the Roman economy, providing finance for Rome’s future campaigns and assisting with the rapid expansion of Roman towns throughout Europe.

The remains of the mining activities are still visible, especially at Roșia Montană. One hundred thousand male slaves were sent back to Rome to help discourage future revolts.

Map of routes used during the Dacian Wars.

If that were not enough, Legio XIII Gemina and Legio V Macedonica were permanently posted in Dacia. The conquered half (southern) of Dacia was annexed, becoming a province while the northern part remained free but never formed a state.

The dual wars were notable victories in Rome’s extensive expansionist campaigns, gaining Trajan the people’s admiration and support. The conclusion of the Dacian Wars marked the beginning of a period of sustained growth and relative peace in Rome.

Trajan began extensive building projects and was so prolific in claiming credit that he was given the nickname Ivy. Trajan became an honorable civil leader, improving Rome’s civic infrastructure, thereby paving the way for internal growth and reinforcement of the Empire as a whole.

The extent of the Roman Empire under Trajan (117 AD).

With Dacia quelled, Trajan later invaded the Parthian empire to the east, his conquests expanding the Roman Empire to its greatest extent. Rome’s borders in the east were indirectly governed through a system of client states for some time. This lead to less direct campaigning than in the west during this period.

We hope you enjoyed today’s campaign and look forward to having you back again. Be sure to stop by soon for you never know where or when we’ll be headed.

Till next time, Don’t Stop Rome-ing!



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Matyszak, Philip. The Enemies of Rome: From Hannibal to Attila the Hun. Thames & Hudson, 2004. ISBN 978-0500251249.

Schmitz, Michael. The Dacian Threat, 101-106 AD. Caeros Publishing, 2005. ISBN 0-9758445-0-4.

“Assorted Imperial Battle Descriptions”De Imperatoribus Romanis.