The Black Mountains, which loom above the festival site, date to the Devonian Period (416 – 359.2 million years ago). This is the period in which some fish began to evolve legs; and terrestrial life, including the first seed-bearing plants, became established. The mountains are formed from a sedimentary rock, Old Red Sandstone, and have been shaped by glaciers during the ice ages. Old Red Sandstone is useful building material, and has been quarried extensively in the mountain range.
The valley of the river Usk in which Glanusk Park is situated provides a fertile strip through the mountainous landscape, which would have been attractive to people for its wealth of plant and animal resources. The river itself provides a means of transport through the valley to the Severn Estuary, which it meets at Newport. It is likely that people came to this area soon after the last of the ice caps withdrew 11,000 years ago. There is evidence for activity dating from the Mesolithic (c. 11,000 – 6,500 years ago) to the south along the Severn Estuary and also further west in the Brecon Beacons at Waun Fignen Felen where scatters of small flint blades known as microliths have been found.
The earliest archaeological evidence close to Glanusk Park dates to the Neolithic (c 6500 – 4300 years ago). Along the A40 towards Crickhowell there are a few standing stones in front of the Manor Hotel, which are all that remain of a chambered tomb, a type of burial monument consisting of stone-built burial chambers covered with an earth mound. A large standing stone surrounded by a slight mound off Great Oak Road to the east of Crickhowell may also be the remnant of a chambered tomb, and there is another – called Garn Coch cairn – close to the village of Llangattock, south-east of the festival site.
In Glanusk Park itself, on the north side of the river, there is a standing stone known as the Fish Stone, which is thought to date to the Bronze Age (c 4300 – 2700 years ago). It is 4.5 metres tall and has a smooth west face and pitted east face, with edges which are apparently dressed to make it look like a fish standing on its tail. There are other standing stones nearby, for example at Tretower to the north-west and at Llwyn y Fedwyn to the west. These may have formed a series of navigation markers. There is a round barrow, another type of burial monument built of stone and covered in turf, at Cefn Moel to the north-east of Bwlch. There is a small series of these round barrows heading north towards the eastern side of Llangorse Lake.
In the woods above the Fish Stone are the remains of a hillfort, a type of settlement from the Iron Age (c 2700 – 2000 years ago), known as Penmyarth Camp. It may have been surrounded by two large earth and rock ramparts, although now little survives because of rock quarrying. There is a better-preserved hillfort to the north of Crickhowell. This is called Crug Hywel, and gave the modern town its name. A third hillfort, Llangenny Camp, lies to the east of Crickhowell.
There is a Roman fort at Pen y Gaer, near Tretower to the north west. It is quite a small fort, measuring 128 by 90 metres, and would have housed a small garrison of up to 500 foot-soldiers. Two stones engraved with the names of military units were found in the nineteenth century in Tretower Both were built into the walls of houses. A Roman milestone was found south-west of Crickhowell and is now in the Brecon Museum.
One of the grave stones in the private graveyard in Glanusk Park is thought to have originally been an early medieval standing stone. It has been moved from its original site, and was engraved in 1928 with an epitaph to Joseph Henry Russell, the 2nd Baron Glanusk.
In Llangors Lake about 40 metres from the north shore, there is the only crannog in Wales. This is a small artificial island built of layers of stone, earth and brushwood behind large oak timbers. It may have been the home of Tewdwr ab Elise, the King of Brycheiniog, in the late 9th and early 10th Centuries. This site was destroyed in 916 by an army led by Aethelflaed (King Alfred’s daughter), Queen of Mercia. A well preserved wooden canoe dating to the 9th Century was found in the Lake in 1925, and is now in Brecon Museum.
A steep, flat topped mound close to a nineteenth century farmhouse at Maes Celyn on the A40 between the festival site and Crickhowell is thought to be the motte of a Norman castle. In the centre of Crickhowell itself is another motte and bailey castle, first built in the 12th Century, and rebuilt in stone in 1272. It was destroyed in the uprising against English rule led by Owain Glyndŵr at the start of the 15th Century. Part of the bailey and gatehouse are still standing. The remains of another motte and bailey castle may be seen in the village of Tretower.
The castle at Tretower, in which Sir James Berkeley had successfully resisted a siege by Owain Glyndŵr’s forces, was gradually replaced as a family home during the 14th and 15th Centuries by Tretower Court, a fortified manor house which still stands adjacent to the castle.
The estate at Glanusk Park was founded in 1826 by Joseph Bailey, who had made his fortune as an ironmaster – the owner of a forge or blast furnace. Originally, there were two large houses – a mansion house on the south side of the river and the Dower House at Penmyarth on the north side of the river. The southern house was demolished after a fire in 1952. As well as the two houses, the estate comprises a private chapel, Tower Bridge, the gamekeeper’s cottage and numerous agricultural buildings.
(by Matt Law and Alan Lane, Cardiff University. With thanks to Andrew Seaman and Paula Jones)