 In 1758, on the death of the 1st Earl of Arran, his father's second cousin, he unknowingly became "de jure" the 15th Earl of Ormond.It had been believed that all the titles of James Butler, 2nd Duke of Ormond became forfeit in 1715.However, in 1791, it was found that the title of "Earl of Ormond" (and its subsidiary titles) in the peerage of Ireland had merely lain dormant and so were successfully revived by John Butler's cousin, John Butler, 17th Earl of Ormonde.