The Calydonian Boar was a monster in Greek mythology that existed during the Olympian Age. It was sent by goddess Artemis to destroy the region of Calydon, which was in the central-west part of Greece.
Every year, Oeneus, the king of the region, would make sacrifices to the gods, offering them a percentage of the harvest. It all started when one year, he forgot to make a sacrifice to the goddess of the hunt, Artemis, who was infuriated. To punish him and his people, Artemis sent a boar of monstrous size that caused devastation in the surrounding area. To save themselves from the beast, the people sought refuge inside the city walls, but soon hunger made its appearance.
Oeneus sent a message all over Greece asking for help to kill the boar, and giving its pelt and tusk in return. A few brave men answered Oeneus' call, including his son Meleager, as well as a fearless woman, Atalanta. In fact, it was her that caused the first blow to the beast, driving an arrow through its skin, and thus triggering its eventual death. Meleager, who had fallen in love with Atalanta, said that she should get the pelt of the boar, but his uncles, who also participated in the Hunt, protested. The prince, furious, slew them and offered it to Atalanta. When his mother learned what had happened, she burned the final brand that she had tucked away after the Fates had told her it would mean the death of her son, causing Meleager's demise. As a result, Artemis managed to get her revenge from King Oeneus.