Excalibur's name has traveled through several languages on its way into English. Geoffrey of Monmouth, writing in Latin around 1136, calls the sword Caliburnus, itself apparently drawn from an earlier Welsh or Brittonic form; Welsh tradition independently names Arthur's sword Caledfwlch, a compound built from words for hard and breach or gap, suggesting a blade that cuts through what stands in its way. Caledfwlch in turn closely resembles Caladbolg, hard lightning or hard gap, the name of a ferocious sword wielded by the hero Fergus mac Roich in the Irish Ulster Cycle, a body of heroic legend that took shape independently of the Arthurian material and predates Geoffrey's history by centuries in its oral and early written forms. The resemblance between the Welsh and Irish sword names is close enough that most scholars treat them as descending from a shared Insular Celtic story pattern, an unbreakable or supremely destructive named sword, rather than as a coincidence, which would place the germ of Excalibur's story in a Celtic storytelling tradition considerably older than the developed Arthurian legend that eventually gave the sword its own French-derived English name.