Tradition / Region: Welsh Mythology
Alternative names: Cath Paluc, Cath Balug, Chapalu
Category: Cat

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The Myth

Cath Palug was a monstrous cat whose legend became closely associated with the tales of King Arthur. According to Welsh tradition, it was born as a kitten from the great white sow Henwen in Gwynedd. The kitten was cast into the sea but crossed the Menai Strait to the Isle of Anglesey, where it was raised by the sons of Palug. As it grew, it became one of the island’s greatest plagues.

The beast haunted the waters and shores of Anglesey, where it slaughtered countless warriors. One Welsh tradition tells that 180 men fell before the monster before the hero Cai (Kay) confronted it and finally slew it.

In later Arthurian romances, the story changed, replacing Cai with King Arthur himself. Some tales place the monster beside lakes or marshes, where it is described as an enormous black cat—or even a strange fish-like cat—that terrorized all who approached. In one famous version, a fisherman caught a small black kitten in his net after breaking a sacred vow. The kitten grew into a gigantic monster that killed the fisherman, his family, and every traveler who came near the lake until Arthur destroyed it.

Not every legend grants Arthur victory. Some medieval French stories claim the monstrous cat defeated the king, knocking him into a bog before killing him. These versions were widely regarded by other medieval writers as hostile tales intended to mock the Arthurian tradition.

Whether slain by Cai or Arthur, Cath Palug remains one of the most famous monstrous cats of Celtic legend, remembered as a deadly beast born from an unnatural birth whose reign of terror ended only after a legendary battle.

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Sources

“Cat-sìth.” Wikipedia: The Free Encyclopedia. Wikimedia Foundation. Accessed July 28, 2026. https://en.wikipedia.org/wiki/Cat-s%C3%ACth

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