Who was the Greek god of the sea, earthquakes, and horses?

Poseidon was the Greek god of the sea, earthquakes, and horses.

He was one of the twelve Olympians and a son of the Titans Cronus and Rhea. After the Olympians defeated the Titans, Poseidon and his brothers Zeus and Hades divided cosmic realms by lot: Zeus received the sky, Hades the underworld, and Poseidon the sea. The earth itself remained shared among them.

Poseidon’s trident became his defining symbol. Greeks also called him “Earth-Shaker,” linking him to earthquakes, while his older inland cults connected him with horses, springs, and water. He was especially important to sailors, coastal communities, and cities seeking protection at sea.

A common mix-up is to treat Poseidon as only a sea god. His worship combined maritime power with older associations involving horses and subterranean waters. His Roman counterpart was Neptune, but Neptune is not the usual answer for a question about Greek mythology.