Cavall, Arthur's hunting dog.
"And while they listened for the distant hunt,
And chiefly for the baying of Cavall,
King Arthur’s hound of deepest mouth, there rode
Full slowly by a knight, lady, and dwarf;"
Idylls of the King by Alfred, Lord Tennyson. The Marriage of Geraint
"Now this is how Arthur hunted the stag. The men and the dogs were divided into hunting–parties, and the dogs were let loose upon the stag. And the last dog that was let loose was the favorite dog of Arthur, Cavall was his name. And he left an the other dogs behind him, and turned the stag. And at the second turn the stag came toward the hunting–party of Arthur. And Arthur set upon him, and before he could be slain by any other Arthur cut off his head. Then they sounded the death–horn for slaying, and they all gathered round." The Age of Chivalry, or Legends of King Arthur
"And Arthur went himself to the chase, leading his own dog Cavall. And Kaw, of North Britain, mounted Arthur's mare Llamrei, and was first in the attack. Then Kaw, of North Britain, wielded a mighty axe, and absolutely daring he came valiantly up to the boar, and clave his head in twain. And Kaw took away the tusk. Now the boar was not slain by the dogs that Yspaddaden had mentioned, but by Cavall, Arthur's own dog."
"Now when Arthur approached, Twrch Trwyth went on as far as Preseleu, and Arthur and his hosts followed him thither, and Arthur sent men to hunt him; Eli and Trachmyr, leading Drudwyn the whelp of Greid the son of Eri, and Gwarthegyd the son of Kaw, in another quarter, with the two dogs of Glythmyr Ledewic, and Bedwyr leading Cavall, Arthur's own dog. And all the warriors ranged themselves around the Nyver. And there came there the three sons of Cleddyf Divwlch, men who had gained much fame at the slaying of Yskithyrwyn Penbaedd; and they went on from Glyn Nyver, and came to Cwm Kerwyn." The Mabinogion Translated by Lady Charlotte Guest. Kilhwch and Olwen
"There is another wonder in the country called Builth. there is a heap of stones there, and one of the stones placed on top of the pile has the footprint of a dog on it. When he hunted Trwch Trwyth Cafal, the warrior Arthur's hound, impressed his footprint on the stone, and Arthur later brought together the pile of stones, under the stone in which was his dog's footprint, and it is called Carn Cafal. Men come and take the stone in their hands for the space of a day and a night, and on the morrow it is found upon the stone pile." Nennius, British History