According to some early medieval sources, the Siege of Exeter or Siege of Caer-Uisc was a military conflict that took place in or around 630 CE, between the Mercians, led by Penda of Mercia, and the Britons occupying Caer-Uisc (Exeter) in the kingdom of Dumnonia. Penda is said to have laid siege to the town until the exiled British High King Cadwallon of Gwynedd, arrived to confront him.