Short answers, pulled from the story.
The first stone castle on the site of Kilkenny Castle was completed in 1260. The Anglo-Normans had established a presence there as early as 1173, with an initial structure probably built by Richard de Clare, 2nd Earl of Pembroke, known as Strongbow.
Arthur Butler, 6th Marquess of Ormonde, sold Kilkenny Castle to the Castle Restoration Committee in 1967 for a ceremonial £50. The sale transferred the castle to the people of Kilkenny.
Kilkenny Castle served as the capital of Confederate Ireland from 1642 to 1648. The rebel movement's parliament, known as the "Supreme Council", held its meetings at the castle during the Irish Confederate Wars.
Lady Margaret Butler, who was born in Kilkenny Castle around 1454 or 1465, was the paternal grandmother of Anne Boleyn, the second wife of King Henry VIII of England. Lady Margaret was the daughter of Thomas Butler, 7th Earl of Ormond.
Ireland's highest officially recognised air temperature, 33.3 degrees Celsius, was measured at Kilkenny Castle on the 26th of June 1887.
Kilkenny Castle is managed by the Office of Public Works. The gardens and parkland are open to the public, and the Parade Tower serves as a conference venue. Since 2002, the castle has hosted degree conferral ceremonies for graduates of the Kilkenny Campus of the National University of Ireland, Maynooth.