The oldest church in Ardmore was almost certainly timber-built and may well have been one of the earliest Christian churches in Ireland. A good case can be made that St. Declan was a pre-Patrician bishop ie. arrived in Ireland before St. Patrick. Timber churches were probably built in Ardmore until the 700s and 800s from which time onwards stone churches were built. Ardmore cathedral contains the remains of an early stone church and the adjacent Beannacháin is a shrine chapel to St. Declan containing what could well be the 5th century AD grave of the saint. The shrine chapel probably dates to the 8th/9th century when the Cult of Saints grew in observance in Ireland.
Doubt exists about St. Declan, primarily in terms of whether he did precede St. Patrick, because the Latin Life of Declan was written up to 700 years after his death. However, there can be no doubt about the age of the stone buildings in this graveyard. Standing in the east end of Ardmore cathedral the remains of the early church are evident in the south and north walls. Larger blocks of shaped stone are used and were kept when the church was expanded, at different times, to the west and to the east. Compare the image attached to this story to the walls of the chancel as you stand inside in the Cathedral. Can you trace the older stones on both walls?