Local legend has it that St Patrick was shipwrecked on Ynys Badrig (Middle Mouse) and then lived in a cave on the coast below the church he founded at what is now known as Llanbadrig
The rocks here are the world famous Melange, so christened by Edward Greenly when mapping Anglesey because they are literally a complete mixture of limestone, quartzite and green schist.
The cave is actually a hole left where a part of a block of limestone has dissolved away. Similar hollows can be seen everywhere in the Melange, sometimes where humans have quarried the limestone to make lime for the acid soils or for lime mortar. There is a lime kiln just above the cave.
The church is a very quiet tranquil place, nestling on the cliff. Inside [after renovations, fires and restoration] the decoration is unique, with blue Islamic tiles alongside a very ancient carved stone!