In Greek mythology, Athos (/ˈæθɒs/; Ancient Greek: Ἄθως, pronounced [ˈatʰɔːs]) was a giant that Poseidon fought. He is best known for the creation of Mount Athos, a mountain and peninsula in Chalcidice, northern Greece, which is now an important centre of Eastern Orthodox monasticism. In Greek it is commonly called Άγιον Όρος, meaning 'Holy Mountain'.