In Greek mythology, Patroclus was a Greek hero of the Trojan War and an important character in Homer's Iliad. Born in Opus, Patroclus was the son of the Argonaut Menoetius. When he was a child, he was exiled from his hometown and was adopted by Peleus, king of Phthia. There, he was raised alongside Peleus' son, Achilles, of whom he was a childhood friend and close wartime companion. When the tide of the war turned against the Achaeans, Patroclus, disguised as Achilles and defying his orders to retreat in time, led the Myrmidons in battle against the Trojans and was eventually killed by the Trojan prince, Hector. Enraged by Patroclus' death, Achilles ended his refusal to fight, resulting in significant Greek victories.

Greek mythology is the body of myths originally told by the ancient Greeks, and a genre of ancient Greek folklore, today absorbed alongside Roman mythology into the broader designation of classical mythology. These stories concern the ancient Greek religion's view of the origin and nature of the world; the lives and activities of deities, heroes, and mythological creatures; and the origins and significance of the ancient Greeks' cult and ritual practices. Modern scholars study the myths to shed light on the religious and political institutions of ancient Greece, and to better understand the nature of myth-making itself.