The present castle at Carreg Cennen dates to the thirteenth century and Edward the first’s program of castle building.  The site itself, however, has been occupied since Roman times  (a cache of Roman coins and four prehistoric skeletons have been unearthed at the site).  The first to build a castle here were the Welsh princes of Deheubarth.

“The first mention of a medieval castle is in 1248 when Rhys Fychan regained control after his mother had handed the castle over to the English out of hatred for her son.

Nothing remains of this earlier castle, the current buildings date back to the late 13th and early 14th centuries. In 1277 Edward I seized control of the castle, and in 1283 he gave it to one of his barons, John Giffard of Brimpsfield in Gloucestershire. It was probably during Giffard’s tenure that the present castle was built.”  http://www.castlexplorer.co.uk/wales/carreg/carreg.php

“Carreg Cennen Castle had a long and eventful history, having changed ownership numerous times. Legendary references place the original fortress in the Dark Ages, held by Urien Rheged, Lord of Iskennen, and his son Owain, knights during the reign of King Arthur. Stories claim that there is a warrior (perhaps one of the knights, or Arthur himself?) asleep beneath the castle, awaiting a call from the Welsh. The first castle on the site was probably built by the Welsh Lord Rhys, Prince of Deheubarth, in the late 12th century. His descendant, Rhys Fychan, eventually inherited the castle, but was betrayed by his mother (the Norman Matilda de Braeos) who turned over the stronghold to the English. Rhys Fychan regained control of the castle in 1248, but had it taken away by his uncle, Maredudd ap Rhys Gryg, and then seized in 1277 by King Edward I. From that time onwards, the fortress remained in the hands of the English.”  http://www.castlewales.com/carreg.html

“The castle is protected by limestone cliffs to the south and rock-cut ditches to the west. To the north and east there is an outer ward, barbican, gatehouse, drawbridge and deep pits. In the south-east corner of the inner ward steps lead to a vaulted passage and a natural cave beneath the castle. A fresh water spring rises in the cave, which would have been a useful supplement to the castle’s water supply of rainwater cisterns during dry weather. The castle is under the care of Cadw, who have renovated and restored some of the remains. The castle is accessible through a local farm, followed by a steep climb up the hill on which it stands.”  http://en.wikipedia.org/wiki/Carreg_Cennen

Owain Glyndwr’s rebels tried to take the castle in the 1400s.  “In 1402 Sir John Scudamore was actively defending Carreg Cennen Castle in Carmarthenshire against Welsh forces and actually repelling successive onslaughts of Owain Glynd?r. The siege lasted one whole year and considerable damage was inflicted on the castle – in 1416 the repair bills record that the walls had been ‘destroyed and thrown down by rebels’. He is recorded as referring to Owain Glyndwr as a ‘false traytor’ at this time. The castle didn’t fall to the Welsh. Sir John Scudamore as constable of the castle wrote to John Fairford, the Receiver at Brecon: “He (Owain) lay last night at Dryslwynwith Rhys ab Gruffydd, and there I was and spoke to him upon Wales and prayed for a safe conduct under his seal, to send home my wife and her mother and their company, and he would none grant me”.” http://en.wikipedia.org/wiki/John_Scudamore_(landowner)

Carreg Cennen was the primary seat of Cantref Brychan, a division of Deheubarth, until the English conquered the region. http://www.cambria.org.uk/HLC/theme.htm