Nennius recounts two stories that illustrate this; he calls them mirabilia - marvels. The first concerns Carn Cavall, a cairn, or monument, made from stones piled on top of each other, in the Welsh county of Breconshire. On the top of the cairn was a stone bearing the footprint of Arthur’s dog, Cavall, who had marked it by treading on it during a boar hunt. Arthur had built the cairn as a memorial to his beloved dog; whenever the stone with the footprint was removed, within twenty-four hours, it would be back on its heap.
