|Ruler||King Gwyddno Garanhir|
Cantref Gwaelod lay below sea-level and so requried defending by a giant dike encircling the coast. These large earthen dams had to be be constantly maintained.
The weather was normally very clement in Cantref Gwaelod - it was said a hide of land here was worth four hides elsewhere, and that even the peasants could afford to ride horses.
Cantref Gwaelod was a proudly independant kingdom which held an isolationist bent. It tended to keep itself to itself, relying on it's excellent harvests to survive.
Cantref Gwaelod was a Pagan kingdom, though a small British Christian population existed amongst the nobility.
A delegation on behalf of King Uther Pendragon visits. Led by Sir Geriant, these knights seek to convince King Gwyddno Garanhir to join them in their battle against the Saxons. The King refuses to commit but does promise to consider it - especially after Sirs Aeron, Madog and Leander unmask Queen Tryamor as a traitress. She was burnt for her crimes and, on her death, gave a final curse - she said Gwyddno would be the last king, and on his death the land would die.
King Gwyddno Garanhir took Sir Seithenin and other knights to aid the Britains again at the Battle of St Albans. Though the battle was a victory for the British, the Saxons poisoned the wine at the lord's dining hall and King Gwyddno died of poison. On his death, a powerful storm hit Gwaelod, breaking the flood defences and drowning most of the population. A small contingent survives escaped to Norgales, Estregales and other nearby regions.
Cantref Gwaelod is a mythical kingdom which was said to sit where the Cardigan Bay now lies, and supposedly sank below the ocean. As such it is sometimes called "the Welsh Atlantis".
Wikipedia has more information on these myths and the archeological attempts to see if the stories have any proof.