Gawaine, Kay, and Bishop Baldwin lodged with him after becoming lost during a hunt. The Carl beat Baldwin and Kay after they insulted him. He put Gawaine through several tests (including, in one version, a Beheading Game) and was ultimately impressed with his courtliness and his willingness to obey his host.
He had become a giant because of a spell which was broken when, at his own behest, his head was duly cut off by Gawaine. Arthur knighted him and made him Lord of Carlisle. He explained to Gawaine that as a youth he had made a vow to test all those who lodged with him, and to kill those who failed. Gawaine’s nobility freed him from the vow. In reward, he gave Gawaine his lovely daughter in marriage.
Arthur made him the lord of Carlisle and gave him a seat at the Round Table. The Carl founded an abbey in honor of the many knights he had slain. Some say he took the name Carl only after he had become Lord of Carlisle.
Syre Gawene and the Carle of Carlyle | c. 1400
The Carle off Carlisle | Early 16th century