It was rebuilt and became known in Irish as An Chill Mhór (meaning Great Church) and anglicised as Kilmore, which gave its name to the diocese, a name which has remained ever since.

During the Reformation, the Roman Catholic diocese lost possession of the cathedral and all the other temporalities and passed into the hands of the Church of Ireland.

In 1862, Cavan parish church was extended and it became the new cathedral of the diocese under Bishop James Browne.

The nave is lined with columns which extend down both sides, and unusually turn to form what could appear to be the beginning of a rood screen.

The church is beautifully built in a white granite by John Sisk & Son at a total build cost of £209,000.