The Mother Church of Mourne
I’am mentioning this because it was the centre for the early Church in Mourne, dedicated to St. Colman in the 6th Century, now derelict.
But more importantly, it was built inside a Rath, of which the remains can still be traced and whose curving wall forces Newcastle street to swing round sharply before it drops to the river crossing.
Note: There is an abundance of Raths or Ring-Forts sites in the plain of Mourne. My count is of 56 sites, although many have been partially or completely destroyed. They are known locally as Forths.