Trajan's Dacian Wars (101-106): How Rome Conquered Dacia

Trajan’s Dacian Wars were two campaigns, in AD 101-102 and AD 105-106, in which the Roman emperor Trajan defeated King Decebalus of Dacia, in what is now Romania. They ended with the destruction of the Dacian kingdom, the death of its king and the creation of the province of Dacia, one of the last major territorial conquests of the Roman Empire. The wars are commemorated on Trajan’s Column in Rome and remain central to Romanian national history.

Background: Rome and Dacia

The Dacians were an Indo-European people living north of the lower Danube, around the Carpathian arc. In the 1st century BC the king Burebista briefly united them into a powerful state, which broke apart after his death. By the late 1st century AD a new king, Decebalus, had rebuilt a strong kingdom centred on the fortified mountain sanctuary of Sarmizegetusa Regia in the Orăștie Mountains.

In AD 85-86 the Dacians raided the Roman province of Moesia, south of the Danube, and killed its governor, Oppius Sabinus. A Roman counter-attack under the praetorian prefect Cornelius Fuscus ended in disaster, with Fuscus killed. A victory at Tapae in AD 88 restored Roman pride, but in AD 89 the emperor Domitian made peace. Decebalus became a client king and received Roman money and technical experts. Many Romans considered the settlement humiliating, and it was resented long after Domitian’s assassination in AD 96.

The First Dacian War (AD 101-102)

Trajan, a soldier-emperor who came to power in AD 98, prepared carefully. He improved roads along the Danube, including a road cut into the cliffs of the Iron Gates gorge, and gathered a very large army. Ancient sources give no reliable total, and modern estimates for the forces involved range widely, often put at well over 100,000 legionaries and auxiliaries.

On 25 March 101 the Arval Brothers in Rome made vows for Trajan’s safe return as he set out. His army crossed the Danube on pontoon bridges near Viminacium and Lederata and advanced into the Banat. A hard-fought battle near Tapae, in the passes leading towards Sarmizegetusa, ended in a Roman victory but did not decide the war.

In the winter of 101-102 Decebalus and his allies, including Roxolani horsemen, counter-attacked across the lower Danube into Moesia. Trajan intercepted them, and heavy fighting took place in the Dobruja region. The site at Adamclisi in Romania, where the victory monument called the Tropaeum Traiani was later dedicated in AD 109, is usually linked to these battles.

In 102 the Romans pushed into the mountains and captured several Dacian strongholds. Decebalus sued for peace. He agreed to surrender his weapons, siege engines and Roman engineers, to demolish fortresses, to give up territory and to accept a Roman garrison near his capital. Trajan returned to Rome, celebrated a triumph and took the title Dacicus.

The Second Dacian War (AD 105-106)

Decebalus did not keep the terms. He rebuilt forts, recruited deserters and attacked the Iazyges, a people allied to Rome. In AD 105 the Senate again declared war. Decebalus captured the Roman commander Gnaeus Pompeius Longinus by treachery and tried to bargain with him; Longinus took poison rather than become a hostage.

By this time Trajan’s architect, Apollodorus of Damascus, had completed a permanent bridge across the Danube at Drobeta (modern Drobeta-Turnu Severin). Standing on about 20 masonry piers and well over a kilometre long, it was one of the longest bridges built in the ancient world. Trajan left Rome in June 105 and in 106 led his armies through the mountain passes towards Sarmizegetusa Regia.

The capital fell after a siege in the summer of 106. Decebalus escaped with a small following but, about to be captured by Roman cavalry, killed himself. The tombstone of Tiberius Claudius Maximus, found at Grammeni in northern Greece in 1965, records that this cavalryman captured the dying king and brought his head to Trajan. The head was sent to Rome and thrown down the Gemonian Stairs.

Key people

• Trajan (reigned 98-117), the Spanish-born emperor who led both campaigns in person.
• Decebalus (reigned c. 87-106), king of the Dacians, a capable commander and diplomat who resisted Rome for two decades.
• Apollodorus of Damascus, military engineer and architect of the Danube bridge and later of Trajan’s Forum in Rome.
• Lucius Licinius Sura, Trajan’s close adviser and a senior commander in the wars.
• Tiberius Claudius Maximus, the cavalryman whose tombstone records the capture of Decebalus.

Consequences

Dacia was annexed in AD 106 as a Roman province, covering roughly Transylvania, the Banat and Oltenia. A new capital, Colonia Ulpia Traiana Augusta Dacica Sarmizegetusa, was founded about 40 km from the old Dacian centre. The Legion XIII Gemina was stationed at Apulum (Alba Iulia), and settlers arrived from across the empire, while many Dacians were killed, enslaved or displaced.

The booty was enormous. Cassius Dio reports that the royal treasure, hidden under the bed of a diverted river, was betrayed to the Romans by a Dacian noble named Bicilis. A later writer, John the Lydian, quoting Trajan’s doctor Crito, gives a fantastic figure of 5 million pounds of gold and 10 million of silver, which historians regard as greatly exaggerated. Even so, Dacian gold and the mines of the Apuseni Mountains helped fund Trajan’s Forum, his Column and celebrations in Rome in AD 107 that Dio says lasted 123 days, with some 10,000 gladiators and 11,000 animals.

How we know about the wars

Trajan wrote his own account of the campaigns, the Dacica, but only a single sentence of it survives, quoted by a later grammarian. The main narrative comes from Cassius Dio, a senator writing about a century later, whose books on Trajan survive only in a Byzantine abridgement. As a result, the order of many events and the location of key battles remain uncertain.

Archaeology fills some gaps. Excavations at Sarmizegetusa Regia and other Dacian hill forts, Roman camps in Transylvania, military diplomas and tombstones of soldiers all add detail. The frieze of Trajan’s Column is invaluable but must be read with care, because it is a work of imperial propaganda rather than a documentary record.

Legacy

Roman Dacia lasted only about 165 years. During the crisis of the third century, the emperor Aurelian withdrew from the province around AD 271-275. The wars nevertheless left a deep mark. The spiral frieze of Trajan’s Column is the most detailed visual record of any Roman campaign, and the Tropaeum Traiani still stands in reconstructed form at Adamclisi.

In Romania, the Dacian Wars became a foundation story. Romanian is a Romance language, and from the 18th century scholars and nationalists traced the Romanian people to the fusion of Dacians and Roman colonists. How far a Latin-speaking population survived north of the Danube after Aurelian’s withdrawal is still debated by historians.

Timeline

• AD 85-87: Dacian raids into Moesia; the Roman governor Oppius Sabinus and later Cornelius Fuscus are killed.
• AD 89: Domitian makes peace; Decebalus becomes a subsidised client king.
• AD 101, 25 March: Vows in Rome for Trajan’s departure; the First Dacian War begins.
• AD 101-102, winter: Dacian counter-offensive into Moesia is defeated.
• AD 102: Decebalus accepts peace terms; Trajan takes the title Dacicus.
• AD 105: War resumes; the Danube bridge at Drobeta is completed.
• AD 106, summer: Fall of Sarmizegetusa Regia and death of Decebalus; Dacia becomes a province.
• AD 113: Trajan’s Column, depicting both wars, is dedicated in Rome.

Why it matters

The Dacian Wars were Rome’s last great war of conquest in Europe. They destroyed a powerful kingdom, brought new wealth to Rome and created a province that shaped the language and identity of modern Romania.