The quiet, elegant town of Lismore on the River Blackwater was once the location of a great monastic university founded in the 7th century and frequented by statespeople and luminaries from all over Europe. Prince John of England built the first castle here in 1182, and in the 17th century the estate belonged for a while to the family of Robert Boyle, the father of modern chemistry, before passing through marriage to the dukes of Devonshire.
Present-day Lismore Castle – a vast, battlemented mansion, spreading along a steep slope above the river – dates mostly from the 19th century, and is still the family home of the 12th Duke of Devonshire. Adele Astaire, sister of dance legend Fred, married the son of the 9th Duke and lived here from 1932 to 1944. The castle is not open to the public, but the gardens are one of the county's most popular attractions.