Tal y llyn sits in a huge churchyard which throws into relief its diminutive scale.
The church is said to have been founded by St Peulan himself in the 6th century, but no fabric from this period appears to survive.
The chief glory of the church is what is now the font. This dates from the first half of the 11th century and is almost certainly the product of the same workshop as the fonts at Heneglwys and Llaniestyn and one of the great Celtic crosses now in Penmon Priory. Peter Lord suggests it began life as an altar and that if so 'as an altar of the pre Norman period it is a unique survivor in Wales, and, indeed, in Britain'.