"I begin to sing about Poseidon, the great god, mover of the earth and fruitless sea, god of the deep who is also lord of Helikon and wide Aigai. O Shaker of the Earth, to be a tamer of horses and a saviour of ships! Hail Poseidon Holder of the Earth, dark-haired lord! O blessed one, be kindly in heart and help those who voyage in ships!"

Source: https://www.theoi.com/Olympios/Poseidon.html

"Hear, Poseidon, ruler of the sea profound, whose liquid grasp begirds the solid ground; who, at the bottom of the stormy main, dark and deep-bosomed holdest they watery reign. Thy awful hand the brazen trident bears, and sea's utmost bound thy will reveres. Thee I invoke, whose steeds the foam divide, from whose dark locks the briny waters glide; shoe voice, loud sounding through the roaring deep, drives all its billows in a raging heap; when fiercely riding through the boiling sea, thy hoarse command the trembling waves obey. Earth-shaking, dark-haired God, the liquid plains, the third division, fate to thee ordains. 'Tis thine, cerulean daimon, to survey, well-pleased, the monsters of the ocean play. Confirm earth's basis, and with prosperous gales waft ships along, and swell the spacious sails; add gentle peace, and fair-haired health beside, and pour abundance in a blameless tide."

Source: https://www.theoi.com/Olympios/Poseidon.html