Downpatrick Cathedral in County Down, Northern Ireland, sits elevated above the city streets and is a beautiful place. During the 7-8th century a Christian monastery occupied the hill where the cathedral now sits. This monastery, like so many others, was victim to frequent Viking attacks and in the 11th century a round tower was built beside a stone church, apparently better to withstand attack. The round tower was taken down in 1790, sadly. (Personally it's interesting to me to note that my ancestors would have seen it because they left the area around 1770. It would have been in ruins then.) The remains of the round tower was then used to restore the stone church.
It is generally accepted that the main walls of the Cathedral date from the years after 1220. Then the monks, in a petition to Henry III, King of England, referred to the fact that the House of Saint Patrick, which had often been destroyed and burned, was being rebuilt again. Further destruction took place during the wars with Edward Bruce in 1316 and finally, on the suppression of the monasteries in 1541, the Cathedral was laid waste. Notwithstanding its ruinous state which lasted until 1790, King James I granted a Charter to the Cathedral in 1609, providing for a Dean and Chapter. The Charter also decreed that the Cathedral should be dedicated to the Holy Trinity, as the former Celtic church had been before the arrival of de Courcy. Rather than lose the connection with Patrick, the name began to be used for the growing town, which assumed the name Downpatrick.
Although successive deans continued to be installed within the ruined walls, there were no funds to rebuild the Cathedral until 1790 when Wills Hill, the Earl of Hillsborough (and afterwards first Marquess of Downshire), along with the then Dean, the Honourable and Reverend William Annesley, provided the impetus to commence the restoration.