This site is thought to be that of Carnyllion (Carnwallon) Castle, the original wooden fortification, believed to be the one destroyed by Rhys Grug ‘the turbulent son of ‘The Lord Rhys’ during the conflict of 1215.

Warm Pond in 2002

The mound is believed to be the remains of the original fortification

The Old Castle (Yr Hen Gastell) was built in the vicinity of what was Old Castle Farm, The Old Castle Colliery and The Old Castle Works tinworks. All that remains of the early earthen fortification which was a mound castle, is the mound now surrounded by Pond Twym near Sandy Water Park.

1106 Many historians believe that a mound known as Y Domen Fawr close to Hen Gastell was the site of the first wooden fortification established around this time and known as Carnwyllion (Carnwallon) Castle. Today the mound on which the castle was believed to have been built lies in Pond Twym alongside the new road leading from Seaside to Sandy.

1189 Henry II died, open warfare had returned to South Wales and it is more than likely that during the hostilities Carnwyllion Castle was destroyed.

1190 The Lord Rhys had reclaimed the Lordships of Cydweli and Carnwyllion and set about rebuilding Kidwelly Castle to strengthen his hold on the area. He probably arranged to have Carnwyllion Castle rebuilt at the same time.

1201 Carnwyllion was mentioned as the area where Maredudd ap Rhys was killed by the garrison of Kidwelly.

1215 Rhys Grug, described as the turbulent son of The Lord Rhys attacked the Lordships of Kidwelly and Gower in 1215 and Carnwyllion Castle was destroyed by fire. Following this attack Rhys then went on to take Loughor before attacking the castle of Hugh de Miles at Llandilo Talybont.

1604 A deed dated 18 April 1604 mentions a place called the ‘Oulde Castle’ which was within the Borough of Llanelli.

1759 Oulde Castle was referred to again.

1810 The Oulde Castle site was referred to as ‘Y Domen Fawr’, a ‘tumulus’ lying half a mile out of Llanelli by Yr Hen Gastell. This appears to be a reference to the building known as Old Castle Farm or Hengastell Fawr, which was demolished around 1810 to make way for General Warde’s new colliery.

1839 The River Lliedi meandered North from the present Old Castle Road and entered the estuary below Sandy. Two farms known as Hengastell Fawr and Hengastell Fach, which formed part of the Stradey Estate, lay between the river and the shore. Close to the eastern side of a tortuous meander in the River Lliedi, in one of the fields belonging to Hengastell Fawr, stood a mound. The field in which the mound stood was named ‘Baily’. In 1839-40 the course of the River Lliedi was diverted to improve scouring at the Carmarthenshire Dock, which cut off the former course of the River.

1860 A group of workmen undertook an excavation of the site in the latter part of the 19th century when the mound was cut to the centre. Nothing of any importance was discovered and the notes recorded that the site was of ‘ancient' British origin.

1890 A reservoir was created within the bounds of the former meander of the River Lliedi to serve the new adjacent Old Castle Tinplate Works and the mound was left as an island, with about two or three metres remaining above the water. The comment was made that it was surprising that it had survived at all and it was probably only its reputation as a ‘tumulus’ that saved it.

1920 The Transactions of the Carmarthenshire Antiquarian Society and Field Club (1918-21) record that the Mayor, who was also the Chairman of the Old Castle Tinplate Works, took members to a vantage point in Llanelli Park, where it was possible to have a close look at the Norman mound or motte, known as the ‘Old Castle’. Industrial development of the latter part of the 19th century caused the mound to be surrounded by water. The mound, which became accessible only by boat, was covered in grass and appeared to be green. Prior to being submerged it was said to be about 20 feet high surrounded by a ditch, with a bailey attached.

2001 An article written by Roger L Jones, now living in Wolverhampton, appeared in the Llanelli Star recording ‘Fond memories of Pond Twym’. He describes how Pond Twym was used as a cooling pond for the steel works and the water was so hot that it made a perfect environment for fish. He relates that the fish originally found their way to the pond when a drunk who had won some fish at the local fairground, accidentally tipped them into the pond.

Goldies and Blackies thrived in the hot water and local children armed only with sticks, cotton and a bent pin fished in the pond. Sometimes there were so many fish that bait was not necessary and the fish were attracted by the brightness of the silver coloured pins. Many youngsters sailed out to the site of the castle in makeshift boats made from metal tar barrels after straightening them out, turning up the corners and the sides and filling any gaps and holes with remnants of the tar.