Excalibur
Geoffrey of Monmouth, in his "Historia Regum Britanniae" ("The History of the Kings of Britain", c. 1136), Latinised the name of Arthur's sword as "Caliburnus" (potentially influenced by the Medieval Latin spelling "calibs" of Classical Latin "chalybs", from Greek "chályps" ["χάλυψ"] "steel"). Most Celticists consider Geoffrey's "Caliburnus" to be derivative of a lost Old Welsh text in which "bwlch" (Old Welsh "bulc[h]") had not yet been lenited to "fwlch" (Middle Welsh "vwlch" or "uwlch"). In the late 15th/early 16th-century Middle Cornish play "Beunans Ke", Arthur's sword is called "Calesvol", which is etymologically an exact Middle Cornish cognate of the Welsh "Caledfwlch". It is unclear if the name was borrowed from the Welsh (if so, it must have been an early loan, for phonological reasons), or represents an early, pan-Brittonic traditional name for Arthur's sword.
Ancient warfare
In "The Archaeology of Weapons" a broader account of ancient weaponry is taken into account through the investigation of European weapons. Oakeshott believes that at some point between 1500–100 BC that the sword developed from the knife in both Minoan Crete and Celtic Britain and strongly resembles the rapiers. During the Bronze Age in the same general region several other swords were developed: the Hallstatt first appeared during this Age but did not become widely used until the Iron Age, the Carps Tongues, and the Rhone Valley swords. The Hallstatt swords gained prominence during the Iron Age and were a long sword with a rather curious point that was one of three shapes: rounded, a square shape, or similar to a fishtail, and were the preferred weapon for use in a chariot. The Carps Tongues blade were also rather large swords with the edges running parallel for two-thirds of the blade before narrowing to the usually point. The last sword is that of the Rhone Valley and is generally considered more of small sword or an overly large dagger with each hilt uniquely cast in bronze. The pommel of this type of dagger has the ends drawn out into two thin points that curve in towards the blade. Along with Hallstatt swords there were found to be spears, similar to the spearheads found in Mycenae they were quite large at fifteen inches and having a hollow socket however they were unique in that they had a small collar of bronze near where they attached to the shaft.