Solstheim was largely uninhabited until 3E427, when large veins of ebony where discovered and the East Empire Company create the colony of Ravenrock to exploit it. Half of the island, including Ravenrock and most of other settlements, was devastated during the Red year of 4E5, when the Red Mountain of Vvardenfell exploded. Ravenrock served however as a rally point for Dunmer refugees from Vvardenfell and in 4E16, the High King of Skyrim, owner of the island, gave it to the Dunmer to establish their new home.
In 4E201, the southern part of Solsthrim is still endure regular ashfall and explosions from the Red Mountain, hence its rather devastated aspect. In Ravenrock, Dunmer architecture is blending with older building from the Third Era.