Capel Lligwy ( sometimes referred to as Hen Gapel Lligwy ) is a ruined chapel near Rhos Lligwy in Anglesey , north Wales , dating back to the first half of the 12th century . The chapel 's original purpose is unknown , but it might have been used as a memorial chapel or in connection with a local royal court , or as a chapel of ease in a large parish with a growing population . It was used for a time until the early 18th century as a private place of worship for a nearby house , then later fell into disrepair . The walls still remain , with some traces of render on them internally , but it is no roof .