The Lords of the Isles, the heads of Clan MacDonald, once occupied Dunyvaig Castle as their naval stronghold. The castle was the focus of considerable bickering between the MacDonalds and other clans when it was ceded to the crown in 1493 before the Campbell’s of Cawdor finally moved there . The castle’s last tenant, Sir Hugh Campbell, had it destroyed in 1677 after moving to Islay House. Although the castle’s existing remnants are primarily from the 16th century, its foundations date back considerably further, and it is possible that it was built on top of a prehistoric fort or dun.
The tower appears to be in danger due to exposure to the Atlantic gales and high seas, and the eastern side is clearly eroding. Climate change can worsen this erosion.
http://islayheritage.org/wp-content/uploads/2017/10/The-Dunyvaig-Project.pdf