The location where Constantine, Arthur’s grandfather, held his first council of lords when he arrived from Brittany to save Britain from the barbarian hordes.

In Biket’s Lai du Cor Arthur gives the earldom of Cirencester to Caradoc after Caradoc – through a magical horn – proves himself the only knight at Arthur’s court with a completely faithful wife (who was born in Cirencester). Biket claimed that the horn was on display in Cirencester at the time of his writing (1150-1200).

See also
Beneoiz | The Legend of King Arthur
Chastity Test | The Legend of King Arthur