There was a long trial in 1292 of William de Prene, a carpenter in charge of works at Roscommon Castle, who was accused of various frauds in connection with his contract.
A very interesting account of repairs is recorded in 1304 which gives a fair idea of the extent of the fortress. An artilleryman was paid for repairing war engines, and the well was enclosed by a wall 3 feet thick. It was 5 feet across and 32 feet deep, with a wooden cover. Three drawbridges and two portcullisses are also mentioned. The postern was closed with masonry 7 feet thick. The step of the hall repaired, and the tower near it vaulted with two arches. Also St. Bridget’s well was drained into the lake.
Somewhere about this time Felim O’Conor is said to have laid low the castle, while in 1341 his son Hugh was taken prisoner by the King of Connaught and imprisoned in the stronghold, but was released for a ransom the following year.
Roderic O’Conor occupied the castle in 1375.
While in possession of the O’Conors it was a constant source of dispute between O’Conor Don and O’Conor Roe. In 1409, being in the former’s possession, it was besieged by the latter, but the garrison was relieved by Brian O’Conor Sligo, who managed to get provisions into the fortress.
Rory O’Conor died there in 1453. Tadhg O’Conor was treacherously killed by his own people in 1476, and they took the castle of Roscommon, but did not keep it long.
In 1499 the Earl of Kildare led his forces into Connaught, dislodged O’Conor Roe and installed O’Conor Don. In 1512 the Earl of Kildare again took the fortress, and this time he garrisoned it with his own warders. It, however, immediately reverted to the O’Conors, and remained with them until 1566, when it was taken for Queen Elizabeth.
It had been granted to M’William Bourke in 1544, but as he would have had to drive out the occupiers, it is not to be wondered at that he never took possession.
It was restored by the O’Conor Don, and Sir Thomas L’Estrange made constable in 1569. The O’Conor Roe, having a spite against the constable, attacked and burned the castle in 1573, and L’Estrange claimed compensation to the amount of £1,000.
Sir Henry Sydney lodged a night in the castle in 1576, and complained of having no cheer. The O’Conor Don visited him at this time.