Short answers, pulled from the story.
The earldom of Ormond was first created in 1328 for James Butler. It covered a substantial block of territory in the south of Ireland, anchored in what is now County Kilkenny. The Butler family held the title for most of its long history.
Thomas Boleyn received the earldom of Ormond following Piers Butler's resignation in 1528, primarily because his daughter Anne was the mistress of King Henry VIII. His genealogical claim was slim: he was a maternal grandson of the seventh earl. On his death, both the earldom and the related Wiltshire title became extinct, as his son George had already been executed for treason.
Piers Butler was created Earl of Ossory just five days after resigning his rights to the earldom of Ormond in 1528. He was then restored as Earl of Ormond through a new creation in 1538. A parliamentary act in 1544 declared that the 1538 creation was not a new grant but a continuation of the original 1328 earldom.
James Butler was the first Duke of Ormonde. He was made Marquess of Ormonde in 1642, Duke of Ormonde in the Peerage of Ireland in 1660, and Duke of Ormonde in the Peerage of England in 1682. His marriage to his cousin Elizabeth Preston, granddaughter of the third earl, reunited the Ormonde titles with the Ormonde estates.
The Marquessate of Ormonde created in 1825 became extinct in 1997, and the earldom became dormant at the same time. An earlier Marquessate, created in 1816, had already become extinct on the death of its holder. The presumed successors to the dormant earldom are the Viscounts Mountgarret, though neither the seventeenth nor the eighteenth viscount submitted a claim to the Monarch.
The third Marquess of Ormonde did not succeed in restoring the Dukedom. Benjamin Disraeli replied on the 27th of October 1868 and expressed sympathy with the desire to restore "the title of an illustrious ancestor," but implied the political climate made a new dukedom inappropriate. The Dukedom of Ormonde was never restored.