Theobald Butler of Polestown
Theobald Butler was the illegitimate son of Sir James Butler of Polestown and his wife Sabh Kavanagh.
He was the elder brother of Piers Butler, 8th Earl of Ormond and of Edmond Butler of Polestown.
James "Gallda" Butler
James "Gallda" Butler  (died 1434) was the son of James Butler, 3rd Earl of Ormond and
Catherine FitzGerald of Desmond.
From him springs the Cahir branch of the Butler family who were ennobled as Barons Cahir.
Theobald Butler, 1st Baron Cahir
Theobald Butler, 1st Baron Cahir or Caher( died 1596) was an Anglo- Irish peer.
He was the son of Piers Butler of Cahir and the nephew of Thomas Butler, 1st Baron Cahir( of the first creation).
As Theobald's first cousin Edmund, the 2nd Baron, died without issue, the title became extinct.
It was, however, revived on May 6, 1583 in Theobald's favour.
He became the 1st Baron Cahir( of the second creation) and ruled much of the barony of Iffa and Offa West.
Edmond Butler of Killoshulan
Edmond Butler of Killoshulan, Duiske, County Kilkenny( died 12 July 1691) was the youngest son of Piers Butler of Duiske and Margaret Netterville, daughter of Nicholas Netterville, 1st Viscount Netterville.
His grandfather was Edward Butler, 1st Viscount Galmoye.
Killoshulan is a townland in the barony of Crannagh, County Kilkenny.
Richard Butler, 1st Viscount Mountgarret
Richard Butler, 1st Viscount Mountgarret( 1500 – 20 May 1571) was the son of Piers Butler, 8th Earl of Ormond and Lady Margaret Fitzgerald.
He married his half first cousin Eleanor Butler, daughter of Theobald Butler of Polestown, the illegitimate brother of the 8th Earl of Ormond.
He was created 1st Viscount Mountgarret in 1550.
Edward Butler, 2nd Viscount Galmoye
Edward Butler, 2nd Viscount Galmoye( c. 1627 – after 24 October 1667) was the son of Piers Butler of Duiske and Margaret Netterville, daughter of Nicholas Netterville, 1st Viscount Netterville.
His grandfather was Edward Butler, 1st Viscount Galmoye.
Butler succeeded to the title of Viscount Galmoye, in county Kilkenny in 1653 following the death of his grandfather, his father having predeceased him in 1650.
He had a younger brother, Major Edmond Butler of Killoshulan.
Thomas Butler of Cahir
Thomas Butler of Cahir( 1448- 1476) was the grandson of James" Gallda" Butler who was the third son of James Butler, 3rd Earl of Ormond.
He was born and died in Cahir Castle, Tipperary, Ireland.
Piers Butler of Cahir
Piers Butler of Cahir (1425–1464) was the son of James "Gallda" Butler .
He was born and died in Tipperary, Ireland.
Thomas Butler, 3rd Baron Cahir
Thomas Butler, 3rd Baron Cahir or Caher( died) was an Anglo- Irish peer.
He was the son of Piers Butler, the nephew of his namesake the 2nd Baron and the grandson of the 1st Baron.
Thomas Butler, 1st Baron Cahir
Thomas Butler, 1st Baron Cahir or Caher( died 1558) was an Irish peer.
Butler was the son of Thomas Butler of Cahir and Catherine Power.
He was elevated to the peerage of Ireland, 10 November 1543, by the title of Baron of Caher.
He married Eleanor Butler, fifth daughter of Piers Butler, 8th Earl of Ormond.
He lived in Cahir Castle and ruled much of the barony of Iffa and Offa West.
The Baron died in 1558 and was succeeded by his only surviving son and heir, Edmund Butler, 2nd Baron Cahir who died himself two years later.
As he had no legitimate male heirs, the title became extinct.
It was, however, revived in favour of his first cousin, Theobald Butler, 1st Baron Cahir( of the second creation).

Question: Who is the paternal grandfather of Piers Butler Of Cahir?
Answer: James Butler, 3rd Earl of Ormond