Gerald Fitzgerald had unprecedented power in Ireland and jealously guarded his families interests. Fitzerglad was summoned to London in 1534 by King Henry VIII and left his soon Thomas as deputy governor in his absence. Thomas was an exuberant young hothead, known as Silken Thomas for the silk that adorned his men’s helmets. A false rumour spread that the Earl had been executed by the King, enraging Silken Thomas. He charged into St Mary’s Abbey where the King’s Council in Ireland was meeting and threw down the sword of the state in defiance. He immediately began a campaign against the King’s forces in Ireland. His men cut off the water supply to Dublin and laid siege to the city.
The campaign was going well until the Crown forces realised that Silken Thomas has neglected to defend his own stronghold of Maynooth. The English Army attacked the Castle and killed many of the inhabitants. Despite Silken Thomas efforts, he failed to save his family home. He was captured and brought in chains to London where he learned that his father had died of natural causes, rather than execution. There, along with his five uncles, he was hung, drawn and quartered.
This marked what was effectively the end of Fitzgerald ascendancy. By the early 17th century, Maynooth Castle began to fall into disrepair. Richard Boyle, father of the famous scientist Robert Boyle, spent large sums of money renovating the Castle when his daughter married George Fitzgerald who had become a ward of the family. His works involved the demolition of many of the medieval buildings and the Castle suffered further damage during the Catholic Confederacy Wars of the 1640s.
Today the castle is under the care of the OPW, and visitors can enjoy the surrounding grounds while taking in the imposing medieval keep.