Poseidon was the God of the seas and (widely known as the "Earth-Shaker") of earthquakes. He was also the ruler of Atlantis. In Roman mythology, he was known as Neptune. He was integrated into the Olympian gods as the brother of Zeus and Hades, generally considered the second most powerful God after Zeus. Poseidon and Amphitrite, a nymph and ancient sea-goddess and daughter of Oceanus, had many children including Triton, messenger of the sea and herald to Amphitrite, Theseus, the cyclops Polyphemus, and Orion the giant master hunter. He was the patron god of many important sea-faring cities, and was widely prayed for safe voyages, for he could quickly send a tempest to destroy those who disrespected him.