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.
Roland Deschain
Roland is a 30th-generation descendant of his world's version of King Arthur, referred to in the series as Arthur Eld. In "", during a flashback to Roland's time in the Barony of Mejis, a letter from his father identifies Steven Deschain as a 29th-generation descendant of Arthur Eld from a side lineage (that is to say, from one of Arthur's many "gillies," or concubines). Even his guns were originally made of the melted-down metal from the legendary Excalibur sword. It is hinted that one must possess this sword, or another sign of the Eld (the line of Arthur Eld) in order to open the door at the foot of the Tower. According to a supplemental prose story by Robin Furth included in "" (issues #7 & #2, respectively), Roland's ancestry traces back to Arthur Eld and Emmanuelle Deschain, the daughter of his seneschal, Kay Deschain, while the Crimson King's ancestry traces back to an affair between Arthur and the Crimson Queen.