The first historical reference to a castle on the present site in Kilkenny was in 1173, and its construction is traditionally dated at 1172.
The Anglo-Normans had arrived in Wexford in 1169 and quickly took the control of Leinster, the southeast quarter of the island.
Kilkenny, already a monastic village, provided an ideal setting for a fortress a hill beside an established river crossing.
The first castle was probably the motte-and-bailey construction typical of the Norman invasion tactic. This would have consisted of a wooden tower upon a mound of soil, surrounded by an enclosed and fortified lower ground. Indeed, modern archeaology has shown earthworks along at least two lines of the modern castle wings.
William Marshall, a son-in-law of the first invader Richard de Clare, built the stone castle some time in the next few decades. There is no documentary evidence for dating the construction of the stone castle. There is historical mention of a commencement date of 1192, but it is unclear whether this was the beginning of the stone or a reconstruction of the wooden castle.
A raid by the native Irish -- noted in that first historical record of the site -- had expelled the Normans from Kilkenny in 1173, and they were not to return for about 20 years. On their return, under Earl Marshall, they expelled a local clan and the Earl established Kilkenny as the center of his lordship. The castle was to be his seat.
Marshall himself did not visit Kilkenny until 1207, and the record is unclear what state the castle was in by then. The style of construction is similar to the royal castles in Limerick and Dublin, seemingly completed in 1216 and the 1220's, respectively.