Poseidon and the Trojans
You'll read about the Trojan War in Chapter 20, but any overview of Poseidon must mention his relationship with the Trojans, a relationship that's central to understanding this god.
As punishment for their participation in the uprising against Zeus, Poseidon and Apollo were forced to help Laomedon, the king of Troy, build walls around his city. They were to be compensated for this great work, but when it came time to pay, Laomedon refused, angering both gods. After all, the gods had worked hard for an entire year to build the walls. Apollo inflicted a great plague on the city and was satisfied with this revenge. Poseidon sent a sea monster to harass Troy, but his anger continued.
Later, during the Trojan War, Poseidon sided with the Greeks — despite Zeus's order to stay out of the conflict.
Poseidon wasn't always supportive of the Greeks, however. For example, when the Greeks built a wall to protect their fleet of ships, Poseidon complained bitterly to the other gods because he feared the Greeks' wall would become more famous than the wall he and Apollo had built. Poseidon also sometimes harassed Greek sea captains during their voyages.
Because of his anger and bitterness, Poseidon made life hard for everyone during the Trojan War. He was a god who would hold a grudge for as long as it took to get revenge, and his revenge was often brutal. Selfish and disloyal, Poseidon would switch sides without notice, when it suited him. Like the sea itself, he was powerful, changeable, and treacherous.
