Piers FitzThomas Butler
Irish noble
Piers FitzThomas Butler of Duiske (died 1601), was the illegitimate son of Thomas Butler, 10th Earl of Ormond. The lands of Duiske Abbey had reverted to his father. In 1597, the earl executed a deed of conveyance in his favour for the lands (when Piers had reached maturity).
He married Katherine Fleming, the eldest daughter and co-heiress of Thomas, Lord Slane. They had two sons. Piers was succeeded by Sir Edward Butler of Duiske, knt. On 16 May 1646, Edward was created Viscount Galmoye.