The need to preserve the best examples of ancient monuments has long been recognised in legislation. Statutory protection began in 1882 with the first Ancient Monuments Protection Act which initially safeguarded 50 monuments in Great Britain. Wider protection to ancient monuments and archaeological remains of national importance was given subsequently and is now governed by the Ancient Monuments and Archaeological Areas Act 1979 as amended and updated by the Historic Environment (Wales) Act 2016.
The 1979 Act provides the legislative framework for the protection of ancient monuments, supported by guidance issued by Cadw. The Act also embraces properties in the direct care of the Welsh Government, which are managed by Cadw.
Under the 1979 Act, the Welsh Ministers, through Cadw, compile a schedule of monuments. The monuments included on the schedule are of national importance and cover a diverse range of archaeological sites. Some examples may be completely buried below ground, and may only be known through archaeological excavation. Others are far more prominent, and include the great standing ruins of well- known medieval castles and abbeys. The oldest known example is a natural cave — found to contain the earliest evidence of people in Wales — dating to a quarter of a million years ago. At the other end of the spectrum are twentieth-century military structures. Scheduled monuments are often in a ruinous or semi-ruinous condition or take the form of earthworks. More complete structures of national significance are usually protected as listed buildings.
Over 4,000 monuments have now been scheduled across Wales and the number is increasing as part of an ongoing planned policy of enhancing the Schedule. The aim of this enhancement programme is to ensure that the Schedule contains the best examples of all types of ancient monuments in Wales that are of national importance.