When Ardee sub-committee of the County Louth Archeological Society excavated this site in 1953, they found fragments of stained glass and some carved stones which experts have dated approximately to the beginning of the fourteenth century. This suggests that what we see now is a re-building of the earlier church by the Hospitallers after they had taken it over. They may have changed the dedication also, because from this on we find the church called after Saint Catherine, the virgin and martyr of Alexandria, whose feast occurs on November the 25th.

Kildemock remained the property of the Knights Hospitallers for some two hundred and twenty-seven years. Then, came the dissolution of monasteries by Henry VIII and the further great changes in faith and worship known as the Protestant Reformation. For a long time these changes were little felt in country places. Everything went on much as it had always done. But eventually, from the beginning of the seventeenth century, the Crown began to enforce its religious policy in earnest and Catholic rites could no longer be used in the churches. As, however, the people remained Catholic, this meant that churches like ours were not frequented at all. The result was inevitable, and already in 1622 a Royal Visitation of Kildemock found "Church and Chauncell ruynous," a state in which they have continued to the present day.