The Hellenic League was a military alliance formed in ancient Greece, primarily during the 5th century BCE. It was established to unite various Greek city-states against the common threat of the Persian Empire. The league played a crucial role in the defense of Greece during the Greco-Persian Wars, particularly in battles such as Salamis and Plataea. The league was led by prominent city-states, including Athens and Sparta, which provided military leadership and resources. This collaboration among the city-states marked a significant moment in Greek history, showcasing the importance of unity in the face of external threats and influencing future alliances in the region.