The Mabinogion is the earliest collection of prose found in Britain, compiled in the 12th century from spoken word.
They are stories of pre Christian Celtic mythology, and Anglo-French influences.
Based on the story of Rhiannon, a powerful woman who had a son with Pwyll, the prince of Dyfed. One day, the son went missing and Rhiannon is accused of killing him. As a punishment, she is made to sit at the castle gates and tell visitors why she is there. She watched the wild horses that roamed the area and felt drawn to them, often claiming she had seen her son with them. The son was eventually found and delivered to the prince.