Baron Dunboyne was a title first held by the Petit family some time after the Norman invasion of Ireland.

Kiltinan Castle, Fethard, County Tipperary, was the seat of the barons until the Reformation in Ireland.

Following the refusal of the Pope to release him from his vows, he Apostatised, embraced the Church of Ireland and married late in life in the hope of fathering an heir.

However, a distant relative of the 2nd/12th baron was found in County Clare who succeeded to the title.

His ancestry is as follows: James Butler, 2nd/12th Baron Dunboyne married Margaret O'Brien.