Chapters
The Isle of Anglesey (Ynys Môn), known to the Romans as Mona, is located on the northwestern edge of Wales. Separated from the mainland by the Menai Strait, it covers an area of 678.9 km², making it the largest island in the region.
Inhabited since the Mesolithic period, it was historically a stronghold of the Druids, along with nearby Holy Island (Ynys Gybi), as evidenced by the numerous menhirs, cemeteries, and remains of buildings preserved to this day. During the period in question, it was within the sphere of influence of the Celtic tribes of the Deceasans and Ordovicians.
In Welsh, the island is called Môn, the etymology of which is difficult to determine. It is also uncertain whether this name inspired the Latin name for the island or vice versa. In the 12th century CE, the monk and chronicler Gerald of Wales referred to the island as “Mother Wales” (Môn Mam Cymru), referring to the great fertility of the local agricultural land.
The first contact
Britain, known to the Romans since at least the 4th century BCE, when Pytheas of Massalia described its life to a Greek traveller, was first invaded by them only in 55 BC. Julius Caesar, temporarily free from the conflicts in Gaul, launched an expedition against it with two legions. This expedition was unsuccessful, as was another one led a year later. Several tribes from southern Britain did become friends of Rome, but this relationship was dictated by the desire for trade, not by submission to the Republic.
Conquest
The actual conquest of the island did not begin until 43 CE, almost a century later, when Emperor Claudius personally led part of the invasion force, which may have numbered 40,000 to 60,000 men and hundreds of ships. In the following years, command was assumed by Aulus Plautius, a distinguished general and senator, who completed the main, most brutal phase of the conquest of Britain and became its first governor in 46 CE. From then on, successive governors continued the conquest of the island north and west, with varying degrees of success.
Wales, located west of the Roman-occupied territories, became the target of expeditions launched in 47 CE by Plautius’s successor, Publius Ostorius Scapula. However, his plans were thwarted by uprisings from already conquered tribes and Welsh guerrillas under the command of Caratacus, king of the Catuvellaunii, who had been conquered in 43 CE. Despite numerous victories over the natives, Scapula never realized his plans, devoting the rest of his term to stabilizing the territories he already held.
Paulinus on Mona
Suetonius Paulinus, elected governor of Britain in 58 CE, launched a large-scale pacification effort against Wales. After seizing and securing the main part of the region with a network of forts, he turned his attention to Mona, which by this time had become a stronghold for throngs of refugees from the already conquered lands.
Thanks to Tacitus, who collected first-hand accounts of the campaign, we know the details of the conquest of Mona, as described in his Annals. According to the author, the island was attacked around 60-61 CE, when Roman forces crossed the Menai Strait aboard flat-bottomed boats or by swimming. The landing most likely took place near Bangor, at the northern end of the strait, where it is only about 240 meters wide.
The Roman landing was met with resistance from the island’s inhabitants, who awaited the invaders on the beach. Besides the warriors, there were also druids and women who, due to their black dresses, resembled furies. Their prayers and appearance were said to terrify the Roman soldiers, who nevertheless triumphed over the defenders. The battle was bloody, and its immediate aftermath included a fire-scarred march into the interior of the island. The legionaries primarily destroyed places of worship – sacred groves, menhirs, and temples.
Paulinus planned to establish a permanent garrison on the island, but his plans were thwarted by news of Boudica’s uprising. He withdrew from Wales with most of the occupying forces to quell the rebellion, leaving the region free for the next sixteen years, until the governorship of Agricola.
Agricola
The governorship of Julius Agricola, who served from 77 to 84 CE, is also described by Tacitus, who was his son-in-law. This tells us that Agricola participated in the first expedition into Wales as a military tribune in Paulinus’ army, and likely supported him in his battles against Boudica.
During the Year of the Four Emperors, Agricola supported Vespasian, which led to numerous offices for the former in the following years. Among other things, Agricola was appointed commander of Legio XX Valeria Victrix stationed in Britain, replacing the previous commander, who had been removed from office for his numerous offences.
He assumed the governorship of Britain in 77 CE, beginning with a conflict with the Welsh tribe of Ordovicians, who slaughtered a Roman cavalry unit stationed in their territory. The decisive battle with the Ordovicians, after which the remnants of their forces took refuge on Mona, most likely took place near the stronghold of Dinas Dinorwig, just three kilometres from the Menai Strait.
According to Tacitus, Agricola, as an experienced commander, could not afford to miss such a good opportunity to finally defeat the natives, so he immediately set out for the island. He had no boats, but he had detached a group of auxiliaries from his army whose task was to swim across the strait and surprise the defenders. The soldiers, themselves Britons, were said to have natural swimming talents, so they rose to the challenge, crossing the Menai near the town of Llanidan, breaking the defenders’ resistance, and taking possession of the island.
And so, peace having been sued for and the island given up, Agricola became great and famous as one who, when entering on his province, a time which others spend in vain display and a round of ceremonies, chose rather toil and danger. Nor did he use his success for self-glorification, or apply the name of campaigns and victories to the repression of a conquered people. He did not even describe his achievements in a laurelled letter. Yet by thus disguising his renown he really increased it, for men inferred the grandeur of his aspirations from his silence about services so great.
– Tacitus, Agricola, translated by A. J. Church and W. J. Brodribb, 1876.
Further history
The Isle of Anglesey fell under Roman rule for the next three centuries. Traces of a Roman fort dating back to the second conquest have been found at Cemlyn, but in later years it was most likely administered from the fort at Segontium, across the Menai Channel. Agriculture and copper mining flourished on the island, as they had before the Roman conquest.
In the mid-4th century CE, new fortifications were built on the island in response to growing threats from land and sea. The Roman garrison likely abandoned the island around 383 CE, when Magnus Maximus, commander of Roman forces in Britain, took most of them to the mainland with the aim of usurping the imperial title.
Magnus was defeated and sentenced to death in 388 CE. Meanwhile, Britain was effectively abandoned by the Empire – in 410 CE, Emperor Honorius ordered the Roman citizens living in Britain to look after their own security from then on.
In the following decades, Mona, later called Anglesey, passed successively through the hands of Irish pirates, Scottish tribes, local Welsh chieftains (even becoming the capital of the Kingdom of Gwynedd), Vikings, and finally the Kingdom of England.
