Lerna Heracles killed it, as the second of his labors. The strong Karstic springs remained; the lake, diminished to a silt lagoon by the 19th century, has vanished. Lerna is notable for several archaeological sites, including an Early Bronze Age structure known as House of the Tiles, dating to the Early Helladic period II (2500–2300 BC). The secret of the Lernaean spring was the gift of Poseidon when he lay with the "blameless" daughter of Danaus, Amymone. The geographer Strabo attests that the Lernaean waters were considered healing: Lake Lerna, the scene of the story of the Hydra, lies in Argeia
Greek mythology existing literary evidence. Greek mythology has changed over time to accommodate the evolution of their culture, of which mythology, both overtly and in its unspoken assumptions, is an index of the changes. In Greek mythology's surviving literary forms, as found mostly at the end of the progressive changes, it is inherently political, as Gilbert Cuthbertson has argued. The earlier inhabitants of the Balkan Peninsula were an agricultural people who, using Animism, assigned a spirit to every aspect of nature. Eventually, these vague spirits assumed human forms and entered the local mythology as gods. When tribes from the north of the