Gough Map may have revealed location of long lost kingdom, researchers find

Stories of a lost kingdom off the coast of Wales date back to the Middle Ages. Now, new research suggests an area where the Kingdom of Cantre’r Gwaelod would have existed, and that the famous Gough Map has helped reveal it.

The researchers – Simon Haslett, Professor of Physical Geography at Swansea University, and David Willis, Professor of Celtic at the University of Oxford – examined the geographical evolution of Cardigan Bay for their article in the journal Atlantic Geoscience.


They found a key piece of evidence in the Gough Map, with the researchers focusing on two islands that are depicted in Cardigan Bay, one between Aberystwyth and Aberdovey and the other between there and Barmouth to the north.

These ‘lost’ islands have not hitherto been the focus of a study and, in reviewing the local geological context, the authors suggest that they are likely to be the remnants of a low-lying landscape underlain by soft glacial deposits laid down during the last ice age which has since been dissected by rivers and truncated by the sea.


Stories dating back to the thirteenth century tell of a place called Cantre’r Gwaelod, which means ‘The Lowland Hundred’. The Black Book of Carmarthen, which was written in the mid-thirteenth century, includes a story of this kingdom being protected by dikes until flooding forced its inhabitants to abandon it.

The Gough Map

Haslett and Willis that the Gough Map offers further evidence of this place. In the article they write:

The two ‘lost’ islands of Cardigan Bay are shown on the Gough Map, which is the earliest known map of Great Britain. The historical map is held in the Bodleian Library of the University of Oxford (ms. Gough Gen. Top. 16) and is so named after its previous owner, Richard Gough, who donated it to the library in 1809. For many years it hung on the wall in the Map Library of the Bodleian but its significance is such that a major project undertaken by the Gough Map Panel has digitised it and made it available online for researchers to utilise. The date of the map is debated with estimates ranging through the fourteenth and fifteenth centuries with c. 1360 often cited, but with advocates for a later date around 1400 or later. It has also been suggested that it is based on an earlier original estimated to date from around 1280 with the surviving version being a revised copy.

They add that the Gough Map is considered to have been well-made, especially when it comes to the coastlines. Therefore the mapmaker may have been correct in depicting these two islands.

Detail of the Gough Map showing Wales with two small islands off the coast.

Parts of Cardigan Bay are very shallow and a handful of causeways come out of the water in this area. For example, Sarn Badrig (which means ‘St. Patrick’s causeway’ in English), lies about four kilometres from the Welsh shore, but can be easily be walked upon. All of this evidence points to land existing there and being farmed, but that gradually being lost to erosion and rising waters.

Sarn Badrig (St Patricks Causeway), Wales – photo by Ian Warburton / Wikimedia Commons

Professor Haslett says that the research, “proposes a provisional framework for the evolution of Celtic coasts along the European seaboard and increases our understanding of potential coastal processes acting along the coast of Cardigan Bay where some towns are vulnerable to climate and sea-level change, and likely to result in some of the first climate change refugees in the UK”.

The article, “The ‘lost’ islands of Cardigan Bay, Wales, UK: insights into the post-glacial evolution of some Celtic coasts of northwest Europe,” by Simon K. Haslett and David Willis is published in Atlantic Geoscience, Vol.58 (2022). Click here to access it. You can also read the preprint version on the Oxford University Research Archive.