Wales · Partial ruin
Caer Gybi
Caer Gybi is a late-Roman coastal fortlet located at the centre of Holyhead on Anglesey, built in the 3rd–4th century as a small naval base and watch post. The site preserves substantial lengths of its three defensive curtain walls and the bases of circular corner towers, with later medieval and religious buildings occupying the interior in subsequent centuries.
Its prime
350
Today
Partial ruin
As it stood in 350
What Caer Gybi looked like in its prime.
A compact Roman fort with three roughly rectangular curtain walls built of grey local rubble laid in a coarse herringbone pattern, walls about 4 m high and 1.5 m thick. Each corner featured a circular watch tower; the north-east tower is the most prominent, rising to about 7.9 m. One side of the fort faced the sea and opened onto a stone quay and slipway. At its prime the walls and towers formed a continuous, intact defensive enclosure.
Its story
The story of Caer Gybi.
A Roman Fortlet and Naval Base, c.300-393
Caer Gybi was a small fortlet and naval base of Roman Wales, in the province of Britannia Superior. The exact date of its construction is unknown; it is believed to have gone up between the late 3rd and the early 4th century, at the centre of what is now Holyhead on Anglesey. It is thought to have been a smaller outpost of the larger fort at Segontium, which was used to defend the west coast against Irish sea-raiders.
The Romans also built a watch tower within Mynydd y Twr, on the top of Holyhead Mountain, possibly used as the fortlet's look-out point. Both were possibly abandoned around 393, when the troops were sent to respond to the revolt of Eugenius of Gaul.
Three Walls and a Fourth Side Onto the Sea
The fort had three defensive walls, with a circular watch tower standing at the corner of each. The fourth side fronted the sea and was probably the site of a quay for the patrolling Roman warships. The herringbone-patterned walls are 4 metres high and 1.5 metres thick.
Remnants of the corner towers are visible, the most prominent being the north-east tower at 7.9 metres tall, though the top section of that tower was possibly rebuilt during the medieval period. An excavation outside the northern walls uncovered a building adjoining the north-west tower, of similar construction to the tower and likely to have been Roman as well.
Maelgwn's Gift to Saint Cybi and the Church Within
In the 6th century King Maelgwn Gwynedd gave the old fort to Saint Cybi, who founded a monastery inside its walls. The Church of St Cybi occupies the site today, together with a small detached chapel, Eglwys y Bedd, which reputedly stands over Cybi's grave.
The walled enclosure is a scheduled monument and a National Monument of Wales, and was listed at Grade I on 26 September 1951.
Step inside
6 places to explore in 350.
The record describes 6 distinct spots at Caer Gybi, including 1 interior: interior of the north-west adjoining building. Create your own photoreal reconstruction and explore every one, more scenes means more rooms, more angles, and more of the place to stand in.
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