The hill in front of these (a small mound form this angle) was a place where three witches apparently met.
One stormy night St Patrick was said to have been ship wrecked on the island of middle mouse below Dinas Gynfor. Being a very strong swimmer (!) he swam across strong currents to a cave beneath the present church of Llanbadrig (Badrig=patrick) finding refuge there and fresh water. He stayed and set up a Llan-thus bringing Christianity to these shores.
The church does date from the 6th century and there is a cave just below the graveyard with a spring running through it, so you never know this tale may have some truth in it.