Short answers, pulled from the story.
Richard de Clare, the 2nd Earl of Pembroke, known as Strongbow, constructed the first fortification on the site in the 12th century. The first stone castle was completed by 1260 and featured a square design with four massive circular towers.
Lady Margaret Butler, born within Kilkenny Castle around 1454 or 1465, was the paternal grandmother of Anne Boleyn. This lineage links the castle to the Tudor court in London through Anne Boleyn, the second wife of King Henry VIII.
During the Cromwellian conquest of Ireland in 1650, Oliver Cromwell besieged Kilkenny Castle and damaged the east wall and northeast tower. The damaged sections were subsequently torn down, leaving scars that took decades to heal before the Duke remodeled the castle in 1661.
Arthur Butler, the 6th Marquess of Ormonde, sold the castle to the Castle Restoration Committee in 1967 for a ceremonial £50. The family sold the property due to rising taxes, death duties, and economic depression that made maintaining the estate unsustainable.
Ireland's highest officially recognised air temperature was measured at Kilkenny Castle on the 26th of June 1887. This record stands as a testament to the changing climate of the region and remains a unique part of the castle's meteorological history.
The Office of Public Works manages Kilkenny Castle as a public asset following its handover in 1967. The castle and its grounds are open to the public, with the Parade Tower serving as a conference venue and the Butler Gallery hosting rotating exhibitions.