In the mass exodus from Essos after the Doom of Valyria, two prominent Valyrian families actually settled (read: conquered) Westeros — the Targaryens and the Velaryons, the latter of which has died out by the time "Game of Thrones" begins. At the time of "House of the Dragon," however, the Velaryons are still very much on the scene and will play a central role in the Targaryen civil war to come.