Achilles the best fighter of the Greeks who besieged Troy in the Trojan War; extraordinarily strong, courageous, and loyal, he had only one weak spot: his heel Admetus the king of Pherae in Thessaly; Zeus punished Apollo by sending him to work for Admetus as a shepherd Aeolus the Greek god of the winds

Agamemnon king of Mycenae; the leader of the Greeks in the Trojan War; courageous, but also arrogant and overly proud agora Greek for gathering place; a central outdoor spot for athletic, artistic, spiritual, and political life in ancient Greek city-states Ajax Greek hero with great strength and courage; fought in the Trojan War; used a large shield in battle ambrosia food of the gods; has healing powers

amphitheater an oval or circular open-air space used for performances or sporting events, with spectator seating built in a semicircle around the stage Aphrodite the Greek goddess of love and beauty

apodesmos a band of material that women in ancient Greece wore around the chest, particularly while participating in sports Apollo the Greek god of the sun, prophecy, music, and healing; the son of Zeus and Leto, and the twin of Artemis Ares the Greek god of war; the son of Zeus and Hera, and half brother to Athena

Argo the ship used by a band of heroes who accompanied Jason on his quest to find the Golden Fleece Argonauts a band of heroes who sailed with Jason on the Argo, in search of the Golden Fleece Artemis the Greek goddess of the hunt and the moon; the daughter of Zeus and Leto, and the twin of Apollo Asclepius the god of medicine; son of Apollo; his temple was the healing center of ancient Greece Athena the Greek goddess of wisdom

Athena Parthenos a giant statue of Athena; the most famous Greek statue of all time

ballista (ballistae, pl.) a Roman missile siege weapon that launched a large projectile at a distant target Batavi an ancient tribe that lived in modern-day Germany; also an infantry unit in the Roman army with Germanic origins Briseis a princess captured by Achilles during the Trojan War, causing a feud between Achilles and Agamemnon that resulted in Achilles refusing to fight alongside the Greeks Bunker Nine a hidden workshop Leo Valdez discovered at Camp Half-Blood, filled with tools and weapons; it is at least two hundred years old and was used during the Demigod Civil War Caesar Augustus the founder and first emperor of the Roman Empire; adopted son and heir of Julius Caesar (see also Octavian) Calliope the muse of epic poetry; mother of several sons, including Orpheus

Calypso the goddess nymph of the mythical island of Ogygia; a daughter of the Titan Atlas; she detained the hero Odysseus for many years Camp Half-Blood the training ground for Greek demigods, located in Long Island, New York

Camp Jupiter the training ground for Roman demigods, located between the Oakland Hills and the Berkeley Hills, in California Cassandra the daughter of King Priam and Queen Hecuba; had the gift of prophecy, but was cursed by Apollo so that her predictions were never believed, including her warning about the Trojan Horse catapult a military machine used to hurl objects

Cave of Trophonius a deep chasm home to the Oracle Trophonius; its extremely narrow entrance required a visitor to lie flat on his back before being sucked into the cave; called “The Cave of Nightmares” due to the terrifying accounts of its visitors Celestial bronze a rare metal deadly to monsters

centaur a race of creatures that is half-human, half-horse

Ceres the Roman god of agriculture; Greek form: Demeter

Chiron a centaur; the camp activities director at Camp Half-Blood

chiton a Greek garment; a sleeveless piece of linen or wool secured at the shoulders by brooches and at the waist by a belt Chrysothemis a daughter of Demeter who won Apollo’s love during a music contest

Circe a Greek goddess of magic

Cloacina goddess of the Roman sewer system