The Franciscan Abbey at Castlelyons was founded by John de Barry in 1307. The architectural style of the abbey is typically Franciscan and it is constructed mainly of limestone, which was readily available in the area as raw material.

According to medieval literature, soon after the Abbey was built, John de Barry handed over possession to his daughter, who was married to David the Earl of Barrymore.

It fell into disrepair soon after the reformation when it was confiscated and never inhabited again.