The story
In 1002 the Annals of Ulster place Brian and Máel Sechnaill at Dún Delca, demanding hostages from Áed and Eochaid. The encounter ended with a truce. The notice offers a rare written glimpse of the place behind Dundalk’s name, within a world of competing kings and negotiated authority. It gives us a recorded political encounter, rather than a foundation ceremony or a street plan.↗1
At Castletown, Dún Dealgan carries several layers of memory. The surviving earthwork is described by the OPW as a late-twelfth-century Norman motte and bailey. The conspicuous ruined tower above it is much later again: the eighteenth-century building known as Byrne’s Folly. Its association with Cú Chulainn belongs to tradition. Looking at the hill today means distinguishing these different stories instead of assigning every visible stone to the heroic past.↗1
Follow the sources
- Annals of Ulster, U1002.8CELT / University College Cork
- Dún DealganOffice of Public Works / Heritage Ireland
Research checked 17 October 2026. Links open the original source.

