In Arthurian Mythology, Arondight was the sword of Sir Lancelot, King Arthur's most "trusted" knight.
The origins of this name are lost in the history of time. Lancelot himself was primarily a Germanic creation, son of King Ban of Brittany. He also received a French name early on, Lancelot du Lac, and the French mythology places him in the care of the Lady of the Lake who, in addition to training young Lance in the arts of chivalry, also gave him his kick ass sword. Still others say the lovely yet adulterous Guinevere gave Arondight to Lancelot, knowing of its power and hoping it would protect him in battle.
In addition to being that famous sword, the name Arondight lives on today as
The sword itself lives on in NetHack - it is a very rare find, and obviously an extremely powerful weapon.