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.
Who did Edward Plunkett, 18th Baron of Dunsany marry?
In 1903, he met Lady Beatrice Child Villiers, youngest daughter of The 7th Earl of Jersey, who was then living at Osterley Park, and they were married in 1904

Question: When did they marry?
Self-contained rewrite: When did Edward Plunkett and Lady Beatrice Child Villiers marry?