Arthur’s sword in Welsh legend, analogous to Excalibur, with which it shares the same root.
Scholars have identified it with Caladbolg (‘hard lightning’), the enchanted sword belonging to Cu Chulainn in Irish mythology.
Notes
– Caled, in Welsh, means ‘hard’, ‘severe’.
– Bwlch, signifies an opening.
See also
Caladbolg | The Legend of King Arthur
Source
Culhwch and Olwen | Late 11th century