About 300,000 years ago, volcanism began occurring to the southwest of the summit (centre top of volcano) then, before activity moved towards the present centre 170,000 years ago.Eruptions at this time built up the first major volcanic edifice, forming a stratovolcano in alternating explosive and effusive eruptions.The growth of the mountain was occasionally interrupted by major eruptions, leading to the collapse of the summit to form calderas.From about 35,000 to 15,000 years ago, Etna experienced some highly explosive eruptions, generating large pyroclastic flows, which left extensive ignimbrite deposits.It is also known as Mungibeddu in Sicilian and Mongibello or Montebello in Italian (the Italian word literally means "beautiful mountain").According to another hypothesis, the term Mongibello comes from the Latin Mulciber (qui ignem mulcet, "who placates the fire"), one of the Latin names of the Roman god Vulcan.Caesarius quotes as his authority for the story a certain canon Godescalcus of Bonn, who considered it a matter of historic fact of the time of Emperor Henry's conquest of Sicily circa 1194.Caesarius employs in his account the Latin phrase in monte Gyber ("within Etna") to describe the location of Arthur's kingdom.
five distinct craters — the Northeast Crater, the Voragine, the Bocca Nuova, and the Southeast Crater Complex (2).
Ash from these eruptions has been found as far away as south of Rome's border, 800 km (497 mi) to the north.
Thousands of years ago, the eastern flank of the mountain experienced a catastrophic collapse, generating an enormous landslide in an event similar to that seen in the 1980 eruption of Mount St. The landslide left a large depression in the side of the volcano, known as 'Valle del Bove' (Valley of the Ox).
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 otherworldly associations of the great, volcanic mountain of their new home.
Mediaevalist Roger Sherman Loomis quotes passages from the works of Gervase of Tilbury and Caesarius of Heisterbach (dating from the late twelfth century) featuring accounts of Arthur's returning of a lost horse which had strayed into his subterranean kingdom beneath Etna.