The little market town of Trim (Baile Atha Truim, "Town of the Elder-Tree Fort") lies on the River Boyne in a fertile plain northwest of Dublin. Here within a small space are gathered remains of a great past both religious and military.
In 1172 Hugh de Lacy, a vassal of Henry II, built a castle on a site close to the spot where St Patrick had
founded a monastery in the fifth century. The castle changed hands several times, being successively fought over, destroyed, rebuilt and enlarged. Richard II held the future Henry V and the Duke of Gloucester prisoner here. In the 14th century the town which had grown up around the castle was fortified with walls and gates. The Irish Parliament met here several times during the 15th century. In 1649 the town fell into Cromwellian hands.