In the neighbourhood are a cromlech and two ruined towers, and crannogs, or ancient stockaded islands, have been discovered in the lough.
Rude earthen or stockaded forts, serving as magazines and places of retreat, were erected; or in some cases use was made of strongholds already existing, such as Dun Almain in Kildare, Dunlavin in Wicklow and Fermoy in Cork.
Warned by the failures of the English against Danish entrenched camps, he introduced the long-neglected art of fortification, and built many burhs stockaded fortresses on mounds by the waterside wherein dwelt permanent garrisons of military settlers.
Crann, a tree), the term applied in Scotland and Ireland to the stockaded islands so numerous in ancient times in the lochs of both countries.
As a rule they have been constructed on islets or shallows in the lochs, which have been adapted for occupation, and fortified by single or double lines of stockaded defences drawn round the margin.