Excalibur
Excalibur was the sword given to Arthur by the Lady of the Lake. Some sources suggest that Arthur gave it to Gawain. After Arthur's last battle he made Bedivere return it to the water where it was grasped by a hand and drawn under. Its scabbard prevented the wearer from losing blood. When Gawain fought the magician Mabon over the fairy Marsique, she obtained the scabbard for him but it subsequently disappeared.

The Welsh name for Excalibur was Caladvwlch, equating linguistically with Irish Caladbolg, the name of a sword borne by heroes in Irish legend, derived from calad (hard) and bolg (lightning).
The Holy Grail :: Excalibur