Apollo is the Greek god of light, healing, spring, prediction and arts. His twin sister is Artemis, the goddess of the hunt. Both belong to the twelve Olympic Gods. As a protector of the arts, he was leader of the nine muses and was revered as the god of healing. He also had the ability to predict the future and he was able to share that knowledge with people. While giving health and protection to his friends, he brought death, illness and destruction to his enemies. So, in the Trojan War, he sent the plague to the Greeks to weaken them.