 St Mary 's has national recognition and statutory protection from alteration as it has been designated as a Grade II listed building – the lowest of the three grades of listing , designating " buildings of special interest , which warrant every effort being made to preserve them " . It was given this status on 12 May 1970 and has been listed because it is " a late Medieval church of exceptionally simple character " . Cadw ( the Welsh Government body responsible for the built heritage of Wales and the inclusion of Welsh buildings on the statutory lists ) also notes that despite its " very poor condition " , St Mary 's " is a virtually unaltered late Medieval building ( even retaining the original roof <unk> ) and in its isolation , is characteristic of many churches on the island . " 
