The mint was opened in 1460, and the following year Christopher Fox was appointed Comptroller.
A Parliament held at Trim in 1465 enacted that any one discovered robbing might be killed, and in Meath their heads were to be sent to the Portreffe of the town of Trim, to be put on the castle wall. Several skulls have been found in the moat.
In 1495 an Act of Parliament passed at Drogheda provided that only Englishmen should be constables of Trim and the other principal castles.
The liberty and lordship of Trim were at this time annexed to the Crown for ever.
In 1541 an order was issued to restore the castle, half the cost of which was to be paid by the country.
A grant was made to Sir James Carroll, Lord Mayor of Dublin, in 1610, to build upon the ruins of the castle a house for the King, and also a jail within the castle enclosure.
Colonel Fenwicke occupied the fortress with a regiment of foot and some troops of horse in 1647. It was in the Royalists’ hands until the fall of Drogheda, in 1649, and the garrison disobeyed the Duke of Ormond’s instructions to destroy the place before letting it fall into the hands of Sir Charles Coote and his army.
It is stated that the yellow steeple near having been treacherously delivered into the hands of the Cromwellians, was used as a vantage point to make the castle untenable, and that afterwards when the Governor of the castle was reinstated he had one side of the tower blown up. It was in a sally from the town of Trim that Sir Charles Coote lost his life.
It is reported Cromwell-spent one night in the castle, but there is no evidence that this is the case.
Adam Loftus sold the castle to Sir James Shean in 1666, and it seems to have been in military occupation in 1690. The whole property was purchased by the Wellesleys, who afterwards sold it to Colonel Leslie.