Segontium (Caernarfon)
Segontium was the Roman town close to the present site of Caernarfon in North Wales.
Centuries before the building of Caernarfon Castle, this was acknowledged to be a strategically important site.
Essentially a military settlement, it was founded around 78 AD, largely to keep a watch on the Isle of Anglesey, whose inhabitants, especially the Druid priesthood, had caused the Romans a considerable amount of trouble.
Segontium, located beside the River Seiont, was known to the Welsh by the name Y Gaer yn Arfor.
After a period of unrest in the late 2nd century, it was rebuilt in stone, and was finally abandoned in 383 by Maximus, when he embarked on his invasion of Gaul.
The impressive remains, excavated in 1921 to 1923 by Sir Mortimer Wheeler, can be visited on the hillside overlooking Caernarfon from the present day town's outskirts.
Also on the site is the Segontium Museum, displaying artefacts from the Roman period.