At the top of the hill, on its eastern side, is a circular mound of earth, hollowed out in the center. This is the remains of a Bronze Age tumulus or round barrow, an example of a prehistoric monument that can be found all over Britain.
Round barrows were used as burial mounds from the Neolithic period (c2200 BC) right through the Bronze Age (c1000 BC) and again in the Anglo Saxon period. They may cover an individual or multiple burials and may also have been used for cremations.
The first castle on the Castell Coch site was probably built after 1081, during the Norman invasion of Wales. It formed one of a string of eight fortifications intended to defend the newly conquered town of Cardiff and control the route along the Taff Gorge.
The Snettisham Hoard or Snettisham Treasure is a series of discoveries of Iron Age precious metal, found in the Snettisham area of the English county of Norfolk between 1948 and 1973. The hoard consists of the metal, jet, and over 150 gold/silver/copper alloy torc