High Quality Content by WIKIPEDIA articles! The Old Church of St Nidan, Llanidan is a medieval church, closed and partly in ruins, in the community of Llanidan, in Anglesey, north Wales. The first church on this site, close to the Menai Strait, was established in the 7th century by St Nidan, the confessor of the monastery at Penmon, Anglesey. The oldest parts of the present structure date from the 14th century. In about 1500, the church was enlarged when a second nave was added on the north side; an arcade of six arches was also built between the two naves. Between 1839 and 1843, a new church was built nearby to serve the local community, partly because of the cost of repairing the old church; much of the old church was thereafter demolished, leaving only part of the western end and the central arcade. The decision was condemned at the time by Harry Longueville Jones, a clergyman and antiquarian, who lamented the "melancholy fate" of what he called "one of the largest and most important in the island of Anglesey". Other appreciative comments have been made about the church both before and after its partial demolition.