https://archive.org/details/04428366.2731.emory.edu/mode/2upLongsword by the Irish writer Thomas Leland, is a medieval romance based on the life of William Longespée, 3rd Earl of Salisbury, the son of Henry II. Published in 1762, in 1767 it was adapted into a play The Countess of Salisbury.
Longsword contains "...mystery, dark dungeons, shipwrecks, abducted damsels, evil monks, and heartless villains", Although titled Longsword, Earl of Salisbury: An Historical Romance, Albert Power views it as the "cornerstone" of the Irish Gothic novel as well.
https://en.wikipedia.org/wiki/Longsword_(novel)