Conversation so far:
When was the Abbey founded by Augusta, Lady Gregory?
On 11 May 1904, the society formally accepted Horniman's offer of the use of the building.
What was significant about the society with Augusta, Lady Gregory formally accepting Horniman's offer of the use of the buildling?
As Horniman was not normally resident in Ireland, the Royal Letters Patent required were paid for by her but granted in the name of Lady Gregory.

Question: What was their first production?
Self-contained rewrite: What was the Abbey with Augusta, Lady Gregory's first production?