The Early Middle Ages fortress, which is now little more than ditches and mounds, was made of wood and constructed on a massive rock outcrop in what is now the suburbs of modern-day Llandudno.

Deganwy was probably first occupied during the Roman period, but was popular in the years following their departure because it was safe from Irish raids.

[7] The Brut y Tywysogion recorded that "the earl of Chester again built the castle of Degannwy, which Llywelyn ap Iorwerth had destroyed for fear of the king.

The programme of work was planned by the University of Wales and funded by the Board of Celtic Studies and the Caernarvonshire Historical Society.

[11] During the excavations a dozen sherds of early medieval pottery which had been imported from the Mediterranean were discovered indicating the far-reaching contacts of Gwynedd's royal dynasty.

In 2009, the Gwynedd Archaeological Trust carried out a geophysical survey of the bailey between the two hills and land immediately north and south of the castle.