Three Castles, One Kingdom: Exploring Dinefwr, Dryslwyn and Carreg Cennen

Wales is famed for its castles, but a small part of Carmarthenshire holds a particularly powerful story. Along the Tywi Valley, three fortresses stand within a few miles of one another: Castell Dinefwr, Castell Dryslwyn and Castell Carreg Cennen.

First published as Castles & Kingdoms in our September/October 2021 edition, Jade Braham’s feature follows the River Tywi, the longest river entirely within Wales, through a countryside shaped by woodland, farmland and steep, strategic hills. From each stronghold, the others feel close enough to belong to one connected story.

That story centres on Deheubarth, the medieval kingdom that covered much of south-west Wales. Its rulers held power from sites including Dinefwr, and their history is threaded through conflict with rival Welsh dynasties, Marcher lords and the English crown.

Castell Dinefwr occupies a commanding hill above the Tywi and the town of Llandeilo. In the 12th century it was held by Rhys ap Gruffudd, known as the Lord Rhys. His reign brought a period of strength and stability to Deheubarth, alongside support for Welsh culture, music, poetry and religious houses such as Talley Abbey.

After the Lord Rhys died, disputes over succession weakened the dynasty. Dinefwr passed between his descendants before falling under English control in 1287. The ruins still overlook a landscape of woods, parkland and river bends, with the castle forming part of the wider Dinefwr estate.

The heart of Deheubarth

A short distance west, Castell Dryslwyn rises from an isolated hill above the Tywi. Founded in the 13th century, it became another important seat of Deheubarth and later the stronghold of Rhys ap Maredudd during his revolt against the English crown.

In 1287, an English force of 11,000 troops was sent to besiege Dryslwyn. Cadw records that the conflict lasted two weeks while siege engines and sappers attacked the defences. A section of the walls was brought down and the castle passed into English hands.

Archaeology has also revealed the community beyond the fortress. The remains of a borough occupied terraces below the castle, showing that Dryslwyn was not only a military position but a place where families lived beside the garrison.

Castell Carreg Cennen provides the most dramatic final chapter. Perched on a limestone crag almost 90 metres above the River Cennen, it dominates the surrounding countryside. A Welsh stronghold stood here before the conquest, although much of the ruin seen today was probably built for John Giffard, a baron loyal to Edward I, at the end of the 13th century.

Resistance, conquest and survival

The site changed hands as rival members of the Deheubarth dynasty fought for control. It was later caught up in Owain Glyndŵr’s rising in the early 15th century, before being deliberately damaged during the Wars of the Roses so that it could no longer serve as a fortress.

Together, the three castles turn a journey through the Tywi Valley into a vivid account of medieval Wales. Their walls speak of princely ambition, family rivalry, resistance and conquest, while their hilltop settings make them rewarding places to explore as summer gives way to autumn.

All three sites remain open to visitors. Conditions, facilities and opening arrangements vary, so check the official visitor pages before setting out.

This Flashback Friday feature is republished from West Wales Life & Style, September/October 2021, pages 34–39. The original story has been lightly edited and historical details checked against current official sources for September 2026.