Caer Gybi Holyhead Roman Fort

Caer Gybi a small Roman fortlet located at the centre of Holyhead within the county of Anglesey, which was once in the Roman province of Britannia. The three-walled fort, with it's fourth side fronting the sea is probably the site of a quay, thought to be part of a late 4th century build, associated with Segontium in Caernarfon, which was formed to defend the west coast of Wales against Irish sea-raiders. In the 6th century, the fort was given to Saint Cybi who founded a monastery on the site. The Church of St Cybi stands within the walled fort today. Holyhead (Welsh Caergybi) is name after the fort.