Conversation so far:
What is Edward Plunkett's title?
Born and raised in London, to the second-oldest title in the Irish peerage
How did Edward Plunkett get this title?
The title passed to him at his father's death at a fairly young age, in 1899, and the young Lord Dunsany returned to Dunsany Castle after war duty, in 1901.

Question: Who did he marry?
Self-contained rewrite: Who did Edward Plunkett, 18th Baron of Dunsany marry?