Mount Etna the southeast and the northeast of the volcanic cone. The name Mongibel is found in Arthurian Romance, as the name of the otherworld castle (or realm) of Morgan le Fay and her half-brother, King Arthur, localised at Etna, according to traditions concerning them derived from the stories told by the Breton "conteurs" who accompanied the Norman occupiers of Sicily. What were originally Welsh conceptions concerning a dwarf king of a paradisal, Celtic underworld became attached to the quasi-historic figure of Arthur as "Ruler of the Antipodes" and were then transplanted into a Sicilian milieu, by Bretons impressed by the already
Mount Etna accessible record of Etna's eruptive history. The most recent collapse event at the summit of Etna is thought to have occurred about 2,000 years ago, forming what is known as the Piano Caldera. This caldera has been almost entirely filled by subsequent lava eruptions, but is still visible as a distinct break in the slope of the mountain near the base of the present-day summit cone. Mount Etna is moving towards the Mediterranean Sea at an average rate of 14 mm per year, the massif sliding on an unconsolidated layer above the older sloping terrain. Eruptions of Etna follow a