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Roman Conquest of Ireland (Hibernia Unanimis)

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Roman Conquest of Ireland
Hibernia Unanimis
Date 82-84, 108-109
Location Ireland
Result Roman Victory
  • Gradual conquest of Ireland
  • Creation of the province of Hibernia
Vexilloid of the Roman Empire Roman Empire

Kingdom of Meath



Commanders and leaders
Vexilloid of the Roman Empire C. Julius Agricola

Túathal Techtmar
Fiacha Cassán

Vexilloid of the Roman Empire Trajan
Vexilloid of the Roman Empire M'. Laberius Maximus
Fedlimid Rechtmar

Elim mac Conrach

and others

Mal mac Rochride
and others

The Roman Conquest of Ireland was a gradual process, beginning effectively in AD 83 under the command of Gnaeus Julius Agricola during the reign of Emperor Domitian. The invasion followed a similar path as that of the conquest of Britain, establishing client states without direct military occupation in many cases. Ireland had experienced frequent trade and contact with the Romans since their settlement of Britain, and by the late first century Ireland was seen as a potential target to protect Roman settlements and trade missions in the region.

Agricola’s invasion would successfully conquer a small area in the east, as well as reinstate an exiled high king named Túathal Techtmar, who had been given refuge by Agricola. Ireland was de jure under Roman rule indirectly. However, the high king only managed to directly control land in the center of Ireland, known collectively as Meath.


The primary source for the Roman account was written by Agricola’s son-in-law, Tacitus, in the Agricola (Latin: De vita et moribus Iulii Agricolae, lit. On the life and character of Julius Agricola), which was written in the year 98 AD. Tacitus’ account would also help describe the culture and history of the British isles before the Roman conquest of Ireland. The Agricola would be Tacitus’ first historical work, written after the assassination of Domitian in 96 AD, which provided the writer with new found freedom.

Irish sources detail aspects of Túathal Techtmar’s rise to power, as well as aspects of his life and the situation in Ireland at the time of Agricola’s invasion. The earliest source involving Túathal Techtmar is a ninth century poem by Mael Mura of Othain, which details how his father, Fíacha Finnolach, was overthrown by the four provincial kings, Elim mac Conrach of Ulster, Sanb, son of Cet mac Mágach, of Connacht, Foirbre of Munster, and Eochaid Ainchenn of Leinster, and that it was Elim who took the High Kingship. Additional details about Túathal Techtmar’s exile are provided by the Lebor Gabála Érenn and the Annals of the Four Masters


Túathal’s Exile

Roman Contact

During Domitian's reign a series of military campaigns would be carried out in the British Isles, under the command of Britannia's proconsul, Gnaeus Julius Agricola, whose son-in-law Tacitus wrote a detailed account of his actions. Agricola arrived to Britannia in the summer of 78 AD, where he was immediately confronted by the insurrection of numerous previously subjugated tribes, including the Ordovices of northern Wales. The Ordovices destroyed a cavalry ala of Roman auxiliaries within their territory, and Agricola planned to march immediately. Using his knowledge of the region from previous military service in Britannia, Agricola was able to react quickly and defeat the Ordovices in battle, effectively exterminating their tribe. From Wales Agricola next marched on the island of Anglesey, forcing its inhabitants to submit. The following year Agricola marched against Brigantes of northern England, as well as the Selgovae along the southern coast of Scotland. Overwhelmed by Agricola's vastly superior numbers, both tribes resubmitted to Roman rule.

Beginning in 71 AD the region of northern England had been subjugated by Rome, beginning with Petillius Cerialis leading a successful war against the Brigantes. Both Cerialis and his successor, Julius Frontinus, would continue to establish a stable border in the north of England. Under both governors, and subsequently Agricola, numerous fortifications would be established along the northern border with the Caledonians. Furthermore, a combination of force and diplomacy ended discomfort among the Britons along the border, allowing Agricola to focus his attention elsewhere.

Around the year 74 AD it is believed that refugees from Brigantia fled to the island of Lambay across the Irish Sea. Over the course of the next decade the island would become increasingly Romanized by merchants, who sought to open the door for Roman trading in the western British Isles. By 80 AD Roman institutions had been established on the island, possibly from numerous skirmishes with the native Brigantes. Following his successful campaign in northern England and Scotland, Agricola returned south to the city of Deva, where he assembled a small party to scout the island to the west. Agricola's expedition would be the first military expedition across the Irish Sea, exploring areas only vaguely known by merchants and traders at the time. Where Agricola landed he established the fort at Drumanagh as a military beachhead, and to protect a local trade post with Irish merchants. It is likely that he planned to use this fort for a future war with the Irish, as at the time Agricola was harboring an exiled Irish prince, Túathal Techtmar, who would be installed as a puppet Irish king under Rome.


The following year it is reported that the Irish became hostile to Roman influence and trade, with the settlement on Lambay Island being raided. Irish kings across the island prepared for war to end these excursions into their territory, prompting an immediate Roman response. Agricola assembled the Roman army at Deva, and according to Tacitus the Roman army consisted of one legion from Britannia, namely the Legio XX Valeria Victrix, under the command of Agricola, supported by large number of British auxiliaries. The Roman army numbered at least 8000 auxiliaries, including four cohorts of Batavians and two cohorts of Tungrian swordsmen, 3000 cavalry, and 17,000 to 30,000 overall. Likewise, with support from the Romans, Túathal Techtmar raised a large army of Irish auxiliaries and allies to join him in his cause. The Legio II Augusta was transferred from southern Britannia to the north to secure the border with the Caledonians. Agricola seemed confident in the security along the border, with this legion fortifying a series of fortifications constructed by Agricola and his predecessors.


Agricola's Campaign

Roman forces under Agricola landed at Drumanagh that year, using the already established fortification to defend against an initial wave of Irish warriors. After the victory at Drumanagh, Agricola pushed further inland, encountering a coalition of Irish nations along a riverside, which the Romans called the Bolinna, from the Irish word Bhóinn. The Irish reportedly outnumbered the Romans marginally, and stood upon high ground, with its front ranks on level ground and subsequent ranks rising in tiers along the slope of the hill, in a horseshoe formation. A brief cavalry charge was also ordered along the level plain between the two armies. After a brief exchange of missiles, Agricola ordered his auxiliaries to launch a frontal attack on the enemy position. Along the lower slopes of the hill the Irish were cut down, while at the top of the hill the remaining army attempted a flanking maneuver. The Irish flanking attempt was in of itself outflanked by the Roman cavalry. As a result the remaining Irish forces were completely routed, fleeing to the surrounding woodland, pursued heavily by the Roman legions.

According to Tacitus the Romans killed a third of the Irish army, with little to no casualties, although this is probably heavily exaggerated. At this time Agricola marched back east, heading toward a settlement known as Eblana, home of the so named Eblani, a tribe along the coastline hostile to the Romans. At the city outskirts an army of the Eblani and Cauci, an allied tribe to the south, marched against the Romans, but were decisively defeated. The city of Eblana was pillaged, with its inhabitants largely slaughtered. At the same time as the advance on Eblana, Túathal Techtmar's army of Irish loyal to him and his brothers, pursued the fleeing Irish into the interior. Upon the hill of Achall he met the Irish high king Elim mac Conrach, who had deposed his father, and defeated him in battle. Elim would be killed, allowing Túathal Techtmar to march on Tara and be crowned king.

Over the next year the forces of Agricola would march south, subjugating the Cauci, before marching west to support the Irish forces loyal to Rome. The Romans reportedly marched as far west as the Lough Ree, encountering hostile forces in a series of skirmishes. The Irish's sparse attacks were largely ambushes and other forms of guerrilla warfare, which slowly dwindled the Roman force. With knowledge of the interior of the island, Agricola returned to Eblana. Túathal Techtmar reportedly defeated armies from Ulster, Leinster, Connacht, and Munster, and he convened a conference at Tara, where he established laws over the island, and annexed territory from each of the four provinces to create the central province of Míde (Meath), centered around Tara to serve as the High King's territory. Four fortresses were constructed in Meath, including Tlachtga, where the druids sacrificed on the eve of Samhain, on land taken from Munster; Uisneach, where the festival of Beltaine was celebrated, on land from Connacht; Tailtiu, where Lughnasadh was celebrated, on land from Ulster; and Tara, on land from Leinster. Meath was officially a client kingdom of Rome, and if the high kingship was any indication, Rome in theory held hegemony over the entire island. Confident in his victory, Agricola departed for Britannia, leaving a small force in Eblana and Drumanagh.

Upon his return to Britannia, Agricola was recalled from the province in 85 by Emperor Domitian, after an unusually long tenure as proconsul. Tacitus theorized that Domitian recalled Agricola, fearing that his success would outshine the emperor's own modest victories in Germany. Agricola returned to Rome, where he was awarded triumphal decorations and a statue, the highest honor Domitian could bestow minus an actual triumph. Agricola would be offered governorship over the province of Africa, but he declined it. In 93 AD Agricola would die on his family estates in Gallia Narbonesis at the age of fifty-three. Rumors persisted that his death was due to poisoning by Emperor Domitian, but no conclusive proof was produced to support such a claim.


Map of Ireland directly after Agricola's conquests.

Trajan's Campaign

Since Agricola's campaign, a section of Ireland, known to the Romans as Hibernia, was ruled directly by the Roman governor of Britannia. His power on the island was consolidated around Eblana, and supported by a legionary station outside the city at Drumanagh. Under Trajan's orders the Legio XXX Ulpia Victrix was moved to Hibernia following the Dacian campaign, where it remained for much of its existence. In 103 AD one of Trajan's generals during the early Dacian campaign, Manius Laberius Maximus, was appointed governor of Britannia. Maximus used the empire's new found wealth after the war to finance large financial projects in Hibernia, which ultimately rebuild Eblana as a Romanized city. Inadvertently Maximus' favoring of Hibernia would lead to the separating of the two regions later in the empire's history.

At this time the Roman Empire owned the entire island in name only, as their client king Túathal Techtmar was high king of all of Ireland, yet he only directly controlled his Kingdom of Meath, with most clans outside the borders of his kingdom ignored his hegemony. Roman knowledge of much of the region remained minimal. However, works such as Ptolemy's Geography included descriptions of much of the island's domestic affairs. During Maximus' governorship Túathal Techtmar began a war against Leinster, burning the stronghold of Aillen and imposing a heavy tribute of cattle on the province. Soon after he also made war on Mal mac Rochride, king of Ulster, and died in battle at Mag Line. Mal mac Rochride took the high kingship for himself, and soon after through off all association with the Romans.

In 108 AD Trajan ordered Maximus to retaliate against the high king, and that year war was declared against Meath and Ulster. Mal mac Rochride was soon joined by Leinster and other major tribes who opposed Túathal Techtmar and his family. The Romans supported Fedlimid Rechtmar, Túathal Techtmar's son. A number of skirmishes in the west of Roman territory were repulsed, although with large casualties for the Romans. These attacks instigated Maximus to lead the Legio XXX Ulpia Victrix after the skirmishers, who fled into the mountains south of Eblana. At the Battle of Mons Lugnaquilla, the Irish forces of Leinster would be routed by Maximus, fleeing as far as the ringfort at Dún Ailinne.

At the same time, a secondary force, primarily of auxiliaries and Irish soldiers under Fedlimid against the Ulaid, defeating and killing Mal mac Rochride at Tara. As a result Fedlimid Rechtmar would be crowned high king over Ireland. Supported by the Romans, Fedlimid did not halt his attacks, instead leading an attack far into Ulster. The Romans eventually turned west, marching as far as the ring fort at Cruachan before returning east. Later that year the Romans, with reinforcements from Britannia, launched an attack on the Navan Fort, the capital of the Ulaid. It is reported by Roman accounts that the Ulaid king, who they called Tipraitius, submitted to Roman rule, allowing the Romans to focus their attacks on the south.

Skirmishers from central Ireland and Munster successfully captured the Irish fort at the Hill of Ward, and launched a partially successful ambush on Roman forces returning to Meath from Ulster. That winter the fort would reportedly be besieged by a larger Roman force and recaptured. Numerous hill forts in Ireland would seemingly weaken the Roman advance significantly, delaying their advance and also serving as a base for raids and ambushes. In early 109 the Romans received the surrender of the defenders at Dún Ailinne, and subsequently slaughtered its garrison. Throughout the next year Roman general Maximus reportedly spent the year campaigning into the south of Ireland, although the extent of his campaign is unclear. It is known, however, that by the end of the year much of the island of Hibernia was firmly under Roman control, or its client kings.

Trajan's war in Hibernia would be a huge success for the Romans, and would lead to renewed Roman influence across the island. A naval expedition ordered by Maximus in 109 would scout out much of the eastern and southern coasts, and would only be elapsed by the later expedition confirming Ireland to be an island. Fedlimid Rechtmar reportedly remained strongly loyal to the Romans, permitting them to build roads and fortifications across Meath, which were largely constructed by the Legio XXX Ulpia Victrix. In the next decade Fedlimid Rechtmar's seat at Tara would also be expanded into a city, with examples of Roman influence springing up around it.


At the end of 109, tensions died down, and Rome and Meath hammered out peace deals with neighboring clans and petty kingdoms. Ulster and Leinster, were forced to pay heavy concessions, becoming tributary states of Rome, similar to Meath. Both of the two were forced to give up much of their land to Meath, and in the case of Leinster, the Romans, who demanded control of Dún Ailinne as an outpost in inland Ireland to check the powers of Leinster, Meath, and the western clans. Rome also seized all of Leinster's coastland for Roman settlements and a planned road stretching from Castra Victrix, the fort where the Legio XXX Ulpia Victrix wintered in 109-110 on the Laoi River in southern Hibernia, up along the coastline to Tara and Eblana.

Much of Ulster's southern lands were taken by Meath, and much of the western section of the kingdom rejected Roman authority and the Romans, without the means to enforce control, were unable to rectify this situation. Anti-Roman sentiment was particularly common in the ringfort of Tulach Óc, located just miles outside of Roman Ulster, and it grew heavily during this time period, with refugees and warriors displaced by Rome finding solace within its walls.

However, rage against the Romans was not exclusive to Ulster, and many surviving Irish skirmishers in the mountains to the south of Eblana continued their activities and raids, joined by vengeful Cauci and Manapii in the region. The rough nature of the area's terrain prevented the Romans from mounting a successful counterattack, and the guerrilla tactics employed by the motley band of Irish in the mountains largely went unopposed.

At the end of 109, Trajan deemed it necessary that Hibernia be separated as a province from Britannia, as due to its increasing size and population, it was no longer feasible for it to stay part of Britannia. Manius Liberius Maximus, governor of Britannia became the first governor of Hibernia, and in Britannia, he was succeeded by Marcus Secundinius Vinicianus, a native Romano-Briton. It was rumored that Trajan split the province of Britannia and moved Maximus to the less-populated province of Hibernia to deter him from a potential usurpation of the empire. Regardless, it appeared that either Maximus received the position well and served as governor of Hibernia until the end of his days.

Although many native Irish were heavily opposed to Roman hegemony in Ireland, most were indifferent and some were even pleased with it, having access to conveniences brought by the Romans and appreciative of the laissez-faire approach to Irish self-government by the Romans. Under these conditions, in the early Second Century, the first major wave of Roman settlers began to emigrate to the eastern Irish coast, establishing towns at the mouths of rivers and beginning Roman economic activity in the region. One of the main reasons Agricola almost dismissed a Roman invasion of Ireland was because it would be expensive and have few economic value, and would also as a troop sink for the military. After eastern Ireland was pacified during Trajan's regime, many Romans were quick to pounce on the economic value of the (almost) virgin shores of Hibernia, thus beginning to fix Agricola's original problem of a Roman Hibernia.

These early settlers were a diverse group, comprised of retired legionaries, merchants, fishermen, and miners for the most part eager to exploit the natural resources and labor pool of the island. Many towns were founded and attracted immigrants but the largest one was Castra Victrix at the mouth of the Laoi River and on a prominent bay in southern Hibernia. A fort had been established there in 109 and was home to the Legio XXX Ulpia Victrix for most of the beginning of the Second Century. This security factor, compounded with the natural harbor, abundant fishing, good pastureland, and nearby copper and gold mines to the southwest led to Castra Victrix, renamed to Portus Victrix in 117.

Following Portus Victrix's newfound prominence, the reach of the Romans began to grow, at least near Portus Victrix, to be more than a thin strip of land on the coast. Roman farmers expanded up the Laoi River, spreading Roman influence inland, and Roman miners established mining colonies in the far southwest coasts of the island to exploit the area's rich gold and copper deposits. Slaves were predominantly used early on, but after several years, local Celts made up the bulk of the labor force. This naturally led to tensions between the locals and the Romans, and several forts were built in the area to keep the peace and prevent full-fledged revolts.
HU Ireland 2

Map of Ireland circa 120.


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