Sir Walter Eustis is said to have been stabbed to death in the castle by his wife’s sister, daughter of the O’More, who had formerly rejected his addresses, but upon the birth of her sister’s child, she murdered Sir Walter in a fit of jealousy, and retired to the convent at Kildare, where she confessed her crime and died penitent.
The O’Dempseys’ seized the fortress in 1329, but the next year it was surrendered to Sir John Darcy, Lord Justice, who restored it to the Earl of Kildare to keep for the King. The O’Dempseys again laid siege to the castle in 1339, but were driven off by the Earl.
O’More, Chief of Leix, burnt Lea in the spring of 1346, but in the following November he was defeated by the Earl of Kildare, who rebuilt the town, castle, and church, but not the steeple.
The fortress was again taken by O’More and O’Dempsey in 1414. Seven years later they were defeated near Kilkea Castle by the 6th Earl of Kildare, nicknamed “Shaun Cam,” or Hump-backed John.
Lea Castle was restored to the Earl after the battle of the Red-bog of Athy.
The Four Masters mention the castle in 1452.
In 1533 the Earl of Kildare furnished the stronghold with guns and ammunition out of the King’s store, and in direct opposition to his commands, which the Master of the Rolls pointed out to him in the presence of the Bishop of Meath.
The following year it is reported to have been one of the six best castles of the Geraldines, and it was the chief stronghold of Lord Offaly, the “Silken Thomas,” during his rebellion, after the fall of Maynooth.
There is a letter from the former constable of this latter fortress, written in 1535, to Cromwell, saying that Lord Thomas had removed the Countess’s apparel to Ley, as well as other valuables, and that he, Boyce, had resigned his office in consequence of the insurrection.
The Carew MSS. record the Castle of Ley was of “no value” in 1537, and state it was granted to James FitzGerald after the attainting of the Earl. In 1548 he required two gunners at the King’s charge, and powder and shot.