From Triassic to Late Cretaceous the western Greece constituted part of the southern Tethyan margin. At the scale of hundreds of kilometres, the whole Alpine belt can be considered as the inverted margin of the Neotethyan Ocean in response to the collision of Apulia against Europe. On a smaller scale of a few tens of kilometres, the various sub basins of the Hellenic Tethyan margin have been inverted to produce the main Hellenic thrust sheets of folded zones. This occurred successively from inner (eastern) zones to external (western) zones.