The Following extract is based on "The Story of Deri" by

               D.G. Llewellyn.  Copy available in Deri Library.

PRE-ROMAN TIMES

The geological structure of the Darran Valley was formed during the Carboniferous period, some 260 million years ago.  The area was intermittently covered by sea and layers of rotting vegetation were compressed by deposits of sands and muds to form coal seams at varying depths.  The mountains were formed when glaciers of the last ice age gouged deeply into the terrain to produce steep sided and narrow floored valleys.

When the Ice Age ended climatic conditions gradually improved but the sub-arctic conditions resulted in a landscape of tundra and steppe where creatures such as the wooly rhinoceros, the cave bear, the wild horse and the mammoth roamed.  The humans who came to Wales around this time were Paleolithic hunters and fishers.  The environment was hostile to man but improved during the Mesolithic Age from around 8,000 to 2,500 B.C.  Mesolithic man scratched a living from the soil with primitive tools and made good use of the natural resources of the land and the increasing number of lakes and rivers.

Shortly afterwards the first real farmers arrived in South Wales.  They came from France by sea and brought the Neolithic way of life.  Evidence of Neolithic man in the area is Carn-y-Bugail or Shepherd's Cairn, a megalithic tomb on the western ridge of the Darran Valley just north of Deri. After Neolithic man came the Beaker Folk, from about 1900 to 1600B.C. followed by Bronze Age Man from about 1500 to 500B.C.

There is evidence of Neolithic Man, Beaker Folk and Bronze Age Man in the Darran valley but little to indicate the presence of Iron Age Man who followed Bronze Age Man in many areas.  By the time the Romans arrived the basic Welshman was in residence in the Darran Valley with the beginnings of the Welsh language.  They were accomplished practitioners of upland farming strongly influenced by their Bronze Age ancestors and had established the broad foundations of local Welsh society. 

The Romans and Anglo-Saxons

The Romans arrived in Britain in A.D. 43 and by A.D. 75 had established a major fort in Cardiff on the site of the present day Cardiff Castle.  Another large fort was built near Brecon and a number of smaller forts were set up between these two major ones.  The largest of these was built between A.D. 103 and 111 at Gelligaer and the main Roman road from Cardiff to Brecon ran along the mountains of the Darran Valley. 

There were many years of bitter fighting between the Roman legions and the Celts during the Roman conquest.  The Silures lived in South East Wales and led by the legendary hero Caradoc put up a fierce resistance to the invaders.  Even after Caradoc's capture and transportation to Rome, the fighting in in Wales continued for another thirty years or so.  Caradoc's is remembered in the Darran Valley by Caradoc's Bridge.  The bridge at this spot close to Groesfan was built originally in the 19th century but the site was a ford much used by the Silures and the Romans.  Another reminder of the Roman presence is the Tegernacus Stone found on the Cefn Brithdir Ridge.  The original stone is now housed in the National Museum of Wales at Cardiff but the original site is clearly marked.  The Romans remained in the area for only a relatively short time and had left Wales by A.D. 383.

After the Romans left the area was successfully infiltrated from the west.  This resulted in probably the first firm and widespread establishment of Christianity into the area.  Churches at this time were made of wood and as a result there is no part of any church in South Wales older than Norman.  A number of splendid stone crosses were erected and many early Christian monuments have been found.  One of the first Christian churches, dedicated to St Gwladys, was on Gelligaer mountain about a mile and a half south west of Deri.  The building of Capel Gwladys proved beyond all doubt that Christianity had a firm foothold by the 5th century.