The gaunt keep and gatehouse of Maynooth Castle stand at the entrance to Maynooth University's South Campus — an atmospheric ruin right in the centre of town. Founded around 1176 by Maurice FitzGerald, 1st Baron Offaly, it became the principal seat of the FitzGerald Earls of Kildare, who were effectively the most powerful magnates in Ireland throughout the 15th and early 16th centuries. At its height it was one of the largest and most impressive castles in the country. Entry is free and the keep is open to visitors in summer months with a small heritage exhibition inside. The grassy courtyard is accessible year-round.
story: > In 1535 the castle was besieged by an English army sent to crush the FitzGerald rebellion. After a week the garrison surrendered on the promise of safe conduct — only to be executed almost to a man. The episode was so shocking it entered the language: "Maynooth pardon" became an Irish phrase for a death sentence dressed up as mercy.