The name 'pillars of Hercules' derives from one of the twelve labours assigned the Greek hero Heracles. Perseus had defeated the Titan Atlas by showing him the head of the Gorgon. Atlas was petrified; his hair became a forest and his shoulders became cliffs. Heracles was then directed to get the Cattle of Geryon and deliver them to Eurystheus. Heracles' way was blocked by the mountain that Perseus had created; to clear a way, he used his mace to split the mountain in half, one part becoming the Rock of Gibraltar and the other becoming a mountain in Morocco. According to the myth, this split in the mountain created a sea link between the Atlantic and the Mediterranean Sea. This link was the Strait of Gibraltar.