23/07/2015
Grennan Castle, Thomastown
Grennan Castle was built by Thomas Fitz Anthony in the 13th Century. Thomas Fitz Anthony son-in-law of Strongbow had been granted a large area of land, originally called Ogenti, the land was renamed by Thomas to Grennan. The townland where the castle is located still maintains that name today, however the village which grew up around the castle gradually became known by the name of its founder 'Thomastown'.
Grennan Castle measures 20 metres x 13 metres and stands 20 metres tall, the walls at their base are 2.5 metres thick. The ground floor contains three barrel vaulted chambers with an entrance to the second floor on the south side by a staircase built hidden into the thickness of the wall. At the top of the staircase is just a gaping opening down to the floor below. This opening was originally covered by a trapdoor, hence with the trapdoor raised the castle was almost impenetrable.
The first floor of the castle contained the great hall, and the second floor reached by a flight of steps in the east wall contained the dormitory area.
In 1650 Cromwell’s troops called to the castle. The siege lasted only two days, the garrison marched out leaving all their weapons behind them and promised to never again oppose English rule.
Grennan Castle survived in good repair until the early 1800s.
Today cattle pass freely through holes in the slowly crumbling castle walls.
