saint marys church new ross

St. Mary's Church was founded probably by William, Earl Marshall, and his wife Isabella between 1207 and 1220, and is possibly the largest medieval parish church in Ireland. It had a nave, chancel, and two transepts, but a 19th century church now occupies the site of the nave and the crossing. The south transept may have been built later than the other parts of the church.

There are three graceful lancet windows in the east gable, and a number of other lancet windows still survive in other parts of the church. Bishop Patrick Barrett who restored the south transept in the 15th century moved from Ferns and established St. Mary's as the diocesan church. The original tower of the church fell in 1763.

In the church is a slab bearing a mask and a cross with the inscription 'ISABEL: LAEGN...' probably Isabel of Leinster; as Isabel was buried in Monmouthshire, this may be a cenotaph. There are other medieval tombs both in the graveyard and inside the modern church.