Sidney Oldall Addy, The Hall of Waltheof — II. Carl's Wark (1893)
“ In Old Norse karl, in addition to its ordinary meaning of man, means an old man, and in this neighbourhood the Devil is popularly known as the Old Lad or the Old One. Carl's Wark then is The Old One's fort, otherwise Odin's fort; and the Norse Sagas represent Odin as an old man with one eye. Grimm has shown how the tales about Odin began to be attributed to the Frankish Charles. [10] Just as the one-eyed Cyclops, according to the ancient fable, built the great walls of the Greek hill-forts, so the one-eyed Odin was the fabulous builder of this strong hill-fort on the Hathersage moors. ”
