Designed by John Roberts and Built in 1793, the Cathedral of the Most Holy Trinity, is almost 220 years old and is Ireland’s oldest Catholic Cathedral. In 2000, the square near Barronstrand Street (formerly known as “Red Square”) was re-named as “John Roberts Square” in light of the influence he had over the architecture of the two Cathedrals in Waterford.

A chapel had previously stood on the same ground, having been constructed there at the height of the Penal Laws on the request of the Roman Catholic community of Waterford.

In the early part of the twentieth century, railings separated the church from the street. These have since been removed. The Cathedral was refurbished in 1977 and a new altar was installed so that Mass could be celebrated ad populum (facing the people). A gift of ten crystal chandeliers from Waterford Crystal enhanced the glory of the Cathedral. A complete reflooring of the building and a restructuring of the sacristy took place in the early 1990s. Further work was completed in November 2006 with a re-fit of structure to the interior and exterior.