This name appears briefly in a poem in the Black Book of Carmarthen in the form Kyrridven [1] and in a poem in the Book of Taliesin in the form Kerrituen [2]. Some theories connect her to an otherwise unattested Celtic goddess of inspiration, and suppose her name is related to Welsh cerdd "poetry".
This name was not regularly given to people until the 19th century [4][3]. It was used by George Eliot for a character in her novel Daniel Deronda (1876).