The Hidden Oracle

by Rick Riordan

  femur bones.

  “Aw, man.” Leo winced. “I’m terrible at sing-alongs. I always clap and do the ‘Old MacDonald’ sounds at the wrong time. Can we skip this?”

  “Oh, no.” I rose to my feet, suddenly feeling better. Perhaps tomorrow I would weep and think about good-byes. Perhaps the day after that we would be flying toward our deaths. But tonight, I intended to enjoy my time with my family. What had Calypso said? Live fully and without fear. If she could do it, then so could the brilliant, fabulous Apollo. “Singing is good for the spirits. You should never miss an opportunity to sing.”

  Calypso smiled. “I can’t believe I’m saying this, but for once I agree with Apollo. Come on, Leo. I’ll teach you to harmonize.”

  Together, the three of us walked toward the sounds of laughter, music, and a warm, crackling fire.

  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

  Clytemnestra the daughter of the king and queen of Sparta; married and later murdered Agamemnon

  Colosseum an elliptical amphitheater in the center of Rome, Italy, capable of seating fifty thousand spectators; used for gladiatorial contests and public spectacles such as mock sea battles, animal hunts, executions, re-enactments of famous battles, and dramas

  Colossus Neronis (Colossus of Nero) a gigantic bronze statue of Emperor Nero; was later transformed into the sun god with the addition of a sunray crown

  Cretan of the island of Crete

  Crommyon a village in ancient Greece where a giant wild sow wreaked havoc before it was killed by Theseus

  cuirass leather or metal armor consisting of a breastplate and backplate worn by Greek and Roman soldiers; often highly ornamented and designed to mimic muscles

  Cyclops (Cyclopes, pl.) a member of a primordial race of giants, each with a single eye in the middle of his or her forehead

  Cyrene a fierce huntress with whom Apollo fell in love after he saw her wrestle a lion; Apollo later transformed her into a nymph in order to extend her life

  Daedalus a skilled craftsman who created the Labyrinth on Crete in which the Minotaur (part man, part bull) was kept

  Daphne a beautiful naiad who attracted Apollo’s attention; she was transformed into a laurel tree in order to escape him

  Demeter the Greek goddess of agriculture; a daughter of the Titans Rhea and Kronos; Roman form: Ceres

  dimachaerus a Roman gladiator trained to fight with two swords at once

  Dionysus the Greek god of wine and revelry; the son of Zeus; activities director at Camp Half-Blood

  Domus Aurea Emperor Nero’s extravagant villa in the heart of ancient Rome, built after the Great Fire of Rome

  Doors of Death the doorway to the House of Hades, located in Tartarus; doors have two sides—one in the mortal world, and one in the Underworld

  drakon a gigantic yellow-and-green serpentlike monster, with frills around its neck, reptilian eyes, and huge talons; it spits poison

  dryads tree nymphs

  Erebos a place of darkness between earth and Hades

  Eros the Greek god of love

  Erythaea an island where the Cumaean Sibyl, a love interest of Apollo, originally lived before he convinced her to leave it by promising her a long life

  Fields of Punishment the section of the Underworld where people who were evil during their lives are sent to face eternal punishment for their crimes after death

  Gaea the Greek earth goddess; mother of Titans, giants, Cyclopes, and other monsters

  Germani (Germanus, sing.) tribal people who settled to the west of the Rhine river

  Golden Fleece this hide from a gold-haired winged ram was a symbol of authority and kingship; it was guarded by a dragon and fire-breathing bulls; Jason was tasked with obtaining it, resulting in an epic quest

  Gorgons three monstrous sisters (Stheno, Euryale, and Medusa) who have hair of living, venomous snakes; Medusa’s eyes can turn the beholder to stone

  Great Fire of Rome a
devastating fire that took place in 64 CE, lasting for six days; rumors indicated that Nero started the fire to clear space for the building of his villa, Domus Aurea, but he blamed the Christian community for the disaster

  greaves shin armor

  Greek fire an incendiary weapon used in naval battles because it can continue burning in water

  Grove of Dodona the site of the oldest Greek Oracle, second only to the Delphi; the rustling of trees in the grove provided answers to priests and priestesses who journeyed to the site

  Hades the Greek god of death and riches; ruler of the Underworld

  harpy a winged female creature that snatches things

  Hebe the Greek goddess of youth; daughter of Zeus and Hera

  Hecate goddess of magic and crossroads

  Hephaestus the Greek god of fire and crafts and of blacksmiths; the son of Zeus and Hera, and married to Aphrodite

  Hera the Greek goddess of marriage; Zeus’s wife and sister

  Hermes Greek god of travelers; guide to spirits of the dead; god of communication

  Herodotus a Greek historian known as the “Father of History”

  Hestia Greek goddess of the hearth

  hippocampi (hippocampus, sing.) half-horse, half-fish creatures

  hippodrome an oval stadium for horse and chariot races in ancient Greece

  Hittites a group of people who lived in modern Turkey and Syria; often in conflict with Egyptians; known for their use of chariots as assault weapons

  House of Hades a place in the Underworld where Hades, the Greek god of death, and his wife, Persephone, rule over the souls of the departed

  Hunters of Artemis a group of maidens loyal to Artemis and gifted with hunting skills and eternal youth as long as they reject men for life

  Hyacinthus a Greek hero and Apollo’s lover, who died while trying to impress Apollo with his discus skills

  Hypnos the Greek god of sleep

  ichor the golden fluid that is the blood of gods and immortals

  imperator a term for commander in the Roman Empire

  Imperial gold a rare metal deadly to monsters, consecrated at the Pantheon; its existence was a closely guarded secret of the emperors

  Iris the Greek goddess of the rainbow, and a messenger of the gods

  Julian dynasty the time period measured from the battle of Actium (31 BCE) to the death of Nero (68 CE)

  karpoi (karpos, sing.) grain spirits

  kouretes armored dancers who guarded the infant Zeus from his father, Kronos

  Kronos the youngest of the twelve Titans; the son of Ouranos and Gaea; the father of Zeus; he killed his father at his mother’s bidding; Titan lord of fate, harvest, justice, and time; Roman form: Saturn

  Labyrinth an underground maze originally built on the island of Crete by the craftsman Daedalus to hold the Minotaur

  Laomedon a Trojan king whom Poseidon and Apollo were sent to serve after they offended Zeus

  Lepidus a Roman patrician and military commander who was in a triumvirate with Octavian and Marc Antony

  Leto mother of Artemis and Apollo with Zeus; goddess of motherhood

  Lupercalia a pastoral festival, observed on February 13 through 15, to avert evil spirits and purify the city, releasing health and fertility

  Lydia a province in ancient Rome; the double ax originated there, along with the use of coins and retail shops

  Marc Antony a Roman politician and general; part of the triumvirate, with Lepidus and Octavian, who together tracked down and defeated Caesar’s killers; had an enduring affair with Cleopatra

  Marsyas a satyr who lost to Apollo after challenging him in a musical contest, which led to Marsyas being flayed alive

  Medea a follower of Hecate and one of the great sorceresses of the ancient world

  Midas a king with the power to transform anything he touched to gold; he selected Marsyas as the winner in the musical contest between Apollo and Marsyas, resulting in Apollo giving Midas the ears of a donkey

  Minos king of Crete; son of Zeus; every year he made King Aegus pick seven boys and seven girls to be sent to the Labyrinth, where they would be eaten by the Minotaur; after his death he became a judge in the Underworld

  Minotaur the half-man, half-bull son of King Minos of Crete; the Minotaur was kept in the Labyrinth, where he killed people who were sent in; he was finally defeated by Theseus

  Mithridates king of Pontus and Armenia Minor in northern Anatolia (now Turkey) from about 120 to 63 BCE; one of the Roman Republic’s most formidable and successful enemies, who engaged three of the prominent generals from the late Roman Republic in the Mithridatic Wars

  Mount Olympus home of the Twelve Olympians

  myrmeke a giant antlike creature that poisons and paralyzes its prey before eating it; known for protecting various metals, particularly gold

  Nemesis the Greek goddess of revenge

  Nero Roman emperor from 54 to 68 CE; the last in the Julian dynasty

  New Rome a community near Camp Jupiter where demigods can live together in peace, without interference from mortals or monsters

  Nike the Greek goddess of strength, speed, and victory

  Nine Muses Greek goddesses of literature, science, and the arts, who have inspired artists and writers for centuries

  Niobe daughter of Tantalus and Dione; suffered the loss of her six sons and six daughters, who were killed by Apollo and Artemis as a punishment for her pride

  nosoi (nosos, sing.) spirits of plague and disease

  nymph a female nature deity who animates nature

  Octavian the founder and first emperor of the Roman Empire; adopted son and heir of Julius Caesar (see also Caesar Augustus)

  Odysseus legendary Greek king of Ithaca and the hero of Homer’s epic poem The Odyssey

  Ogygia the island home—and prison—of the nymph Calypso

  omphalus stones used to mark the center—or navel—of the world

  Oracle of Delphi a speaker of the prophecies of Apollo

  Oracle of Trophonius a Greek who was transformed into an Oracle after his death; located at the Cave of Trophonius; known for terrifying those who seek him

  Ouranos the Greek personification of the sky; father of the Titans

  palikoi (palikos, sing.) twin sons of Zeus and Thaleia; the gods of geysers and thermal springs

  Pan the Greek god of the wild; the son of Hermes

  Pandora the first human woman created by the gods; endowed with a unique gift from each; released evil into the world by opening a jar

  Parthenon a temple dedicated to the goddess Athena located at the Athenian Acropolis in Greece

  Patroclus son of Menoetius; he shared a deep friendship with Achilles after being raised alongside him; he was killed while fighting in the Trojan War

  pegasus (pegasi, pl.) a winged divine horse; sired by Poseidon, in his role as horse-god

  Peleus father of Achilles; his wedding to the sea-nymph Thetis was well attended by the gods, and a disagreement between them at the event eventually lead to the Trojan War; the guardian dragon at Camp Half-Blood is named after him

  Persephone the Greek queen of the Underworld; wife of Hades; daughter of Zeus and Demeter

  phalanx (phalanxes, pl.) a compact body of heavily armed troops

  Phidias a famous ancient Greek sculptor who created the Athena Parthenos and many others

  Polyphemus the gigantic one-eyed son of Poseidon and Thoosa; one of the Cyclopes

  Poseidon the Greek god of the sea; son of the Titans Kronos and Rhea, and brother of Zeus and Hades

  praetor an elected Roman magistrate and commander of the army

  Primordial Chaos the first thing ever to exist; a void from which the first gods were produced

  Prometheus the Titan who created humans and gifted them with fire stolen from Mount Olympus

  Pythia the name given to every Oracle of Delphi

  Python a monstrous serpent that Gaea appointed to guard the Oracle at Delphi

  Rhea Silvia the quee
n of the Titans, mother of Zeus

  Riptide the name of Percy Jackson’s sword; Anaklusmos in Greek

  River Styx the river that forms the boundary between earth and the Underworld

  Saturnalia an ancient Roman festival celebrating Saturn (Kronos)

  satyr a Greek forest god, part goat and part man

  shadow-travel a form of transportation that allows creatures of the Underworld and children of Hades to use shadows to leap to any desired place on earth or in the Underworld, although it makes the user extremely fatigued

  Sibyl a prophetess

  Sibylline Books a collection of prophecies in rhyme written in Greek; Tarquinius Superbus, a king of Rome, bought them from a prophetess and consulted them in times of great danger

  siccae a short curved sword used for battle in ancient Rome

  Sparta a city-state in ancient Greece with military dominance

  Stygian iron a magical metal, forged in the River Styx, capable of absorbing the very essence of monsters and injuring mortals, gods, Titans, and giants; has a significant effect on ghosts and creatures from the Underworld

  Talos a giant mechanical man made of bronze and used on Crete to guard its shoreline from invaders

  Tantalus According to legend, this king was such a good friend of the gods that he was allowed to dine at their table—until he spilled their secrets on earth; he was sent to the Underworld, where his curse was to be stuck in a pool of water under a fruit tree, but never be able to drink or eat

  Tartarus husband of Gaea; spirit of the abyss; father of the giants; a region of the Underworld

  Theodosius the last to rule over the united Roman Empire; known for closing all ancient temples across the empire

  Thracian of Thrace, a region centered on the modern borders of Bulgaria, Greece, and Turkey

  Titan War the epic ten-year battle between the Titans and the Olympians that