It was a small Roman fort in the centre of Holyhead in the Welsh county of Anglesey. It is one of Europe's only three-walled Roman forts, the fourth side was protected by the sea and was probably used as a quay. It is thought to date from the 4th Century and was abandoned in 393.
In the 6th century, the fort was given to Saint Cybi, who used it to build a monastery. The Church of St Cybi still stands on the site today, with a small detached chapel over Cybi's grave.
|Off the A5, in the centre of Holyhead, overlooking the harbour|