Percy Jackson/Heroes of Olympus Timeline

Nico's birthday (while undecided) is stated by Rick Riordan to be January 28th, 1924 (this would mean that his mother's death was around 1934)

• Hazel Levesque is born to Marie Levesque and Pluto.

Nico's birthday (while undecided) is stated by Rick Riordan to be January 28th, 1924 (this would mean that his mother's death was around 1934)

• Grover Underwood is born, the nephew of Ferdinand.

• Thalia Grace is born to Ms. Grace and Zeus.

• Annabeth Chase is born to Frederick Chase & Athena.

• Perseus "Percy" Jackson is born to Sally Jackson and Poseidon.

• Jason Grace is born to Jupiter & Ms. Grace.

• Percy destroys Alecto.
• Master Bolt stolen by Luke Castellan, Son of Hermes.
• Percy Jackson kills the Minotaur on Half-Blood Hill.
• Percy Jackson begins training at Camp Half-Blood.
• Sally Jackson taken by Hades to the Underworld.

• Percy Jackson meets Lord Ares, God of War.

• Percy Jackson, Annabeth Chase and Grover enter the Underworld and meet Hades.

• Percy Jackson duels Lord Ares for the Master Bolt and for the Helm of Darkness, winning the duel.

• Thalia, Percy, and Annabeth meet up with Grover who has been tracking two demigods; Nico and Bianca
• Annabeth is captured by Dr. Thorn.

• Luke Castellan has a fall that would've killed him if he didn't bear the Curse of Achilles from Mount Tamalpais.
• Percy, Grover, Thalia, and Zoë rescue Artemis, goddess of the hunt and the moon, and Annabeth from Dr. Thorn, a manticore.
• Zoë Nightshade is killed from both the poison of Ladon and the blow from her father Atlas, while fighting him on Mount Orthys, the Titan base.
• Atlas is retrapped under the sky. A new constellation is formed by Artemis from the body of Zoë Nightshade, known as "the Huntress". Thalia becomes the new lieutenant of the Hunters of Artemis, declaring Percy Jackson as the child of the Great Prophecy.

• Princess Andromeda sinks beneath the waves, along with several hundred monsters and demigods including Charles Beckendorf.
• Percy Jackson hears the Great Prophecy for the first time.

• Beckendorf's shroud is burned.
• Rachel Elizabeth Dare goes on vacation.

August 16

• Michael Yew goes M.I.A
• The city of Manhattan falls asleep due to Morpheus' enchantment.
• Rachel Elizabeth Dare leaves from vacation.

August 17

• The Clazmonian Sow is unleashed. It is later killed by a Hermes statue and two stone lion statues.
• Hyperion and his army attack at the Central Park reservoir.

August 18

• Titan Army loses the Second Olympian War.
• Kronos' scythe, a.k.a. Backbiter, is destroyed by the Olympian-Goddess Hestia.
• Ethan Nakamura betrays the Titans and becomes the last person to be killed by Lord Kronos.
• Luke Castellan stabs himself to destroy Lord Kronos.
• Titan Lord Kronos is scattered and will most likely never be able to reform again.
• Percy and the Greek Demigod forces successfully fend off the Titan Army from Manhattan and save Mount Olympus.
• Jason and the Roman Demigod forces destroy the Titan base at Mount Othrys, with Jason defeating Krios with his own hands.
• Hades and his Undead Army successfully defend the Empire State Building from the remaining Titan forces.
• Poseidon and his Aquatic Army help defeat Typhon.
• Rachel Elizabeth Dare becomes the new Oracle after the curse is lifted by Hades.
• Percy Jackson makes the Olympians swear on the River Styx to claim their children by the age of 13, give Hades and the minor gods thrones on Olympus cabins at Camp Half-Blood, and to never make a pact of the Big Three. Percy realizes Luke was the true hero.
• The Prophecy of Seven is revealed.
• Percy and Annabeth start dating.

• A Capture the Flag game turns into a search for The Bronze Dragon.

• Aeolus orders all demigods to be killed.
• Venti are released after the death of Typhon.

• Percy forgets his and Annabeth's one-month anniversary.
• The fire-breathing giant Cacus steals Hermes' caduceus.
• Hermes seeks Percy's help to get his caduceus back.
• In a battle against Cacus, Percy and Annabeth learn that Cacus plans to cut off communication among the Olympians, as part of Gaea's plan to overthrow the gods.
• After destroying Cacus, Percy and Annabeth are sent to Paris for their date, as part of Percy's deal with Hermes.
• Around this time, Zeus has been threatening to close off Mount Olympus from mortals.

• Jason Grace, a recently elected praetor, disappears from Camp Jupiter.

• Zeus recalls all the Gods back and closes Olympus, forbidding all contact to demigods and mortals.

December 13-14, 2009

• Percy Jackson goes missing.

April 2010

• Percy Jackson awakes after months in deep sleep by Hera/Juno, begins training with Lupa at the Wolf House.

• Leo, Jason, and Piper must find Leo's table Buford to prevent Bunker 9 from exploding.
• While trying to locate Buford, they end up confronting Dionysus' crazed followers - the Maenads.
• Jason, Leo, and Piper were able to find Buford and prevented Bunker 9 from exploding.

• Quest to stop Gaea and her Giants begins with the Seven (Jason, Percy, Piper, Leo, Hazel, Frank and Annabeth). Camp Jupiter declares war on Camp Half-Blood, causing another Civil War.

• Jason Grace, Piper McLean, and Leo Valdez go to Camp Half-Blood and the Prophecy of Seven is set in motion.

December 17

• Jason Grace, Leo Valdez, and Piper McLean begin their quest to save Hera.

December 20

• Aeolus cancels his order for all demigods to be killed.

December 21

• Jason Grace, Piper McLean, and Leo's due date to rescue Hera from Gaea.
• Porphyrion is resurrected from Tartarus at the Wolf House.
• The Second Giant War begins.

• Percy carries Juno across the Little Tiber and enters Camp Jupiter.

June 19

• Mars gives Frank the quest to free Thanatos.
• The Fifth Cohort wins their first war game in a long time.

June 24

• Percy Jackson leads Roman army and defeats giant Polybotes. Made Praetor of Camp Jupiter.

• Annabeth Chase completes her mission for Athena Parthenos. At the same time, Percy Jackson, Jason Grace, and Piper McLean rescue Nico di Angelo and kill the giants Ephialtes and Otis, with the help of the god Bacchus. Meanwhile, Leo Valdez, Frank Zhang, and Hazel Levesque destroy the eidolons, and Leo recovers the works of Archimedes. Later, Percy, Jason, Piper, Nico, Leo, Frank, Hazel, and Gleeson Hedge rush to the rescue of Annabeth, just as she defeats the spider Arachne. When Arachne falls into Tartarus, Percy and Annabeth follow her into the deepest pit of the Underworld, sacrificing themselves to close the Doors of Death on that side while the others try to reach the doors on the mortal side. On the last request of Percy, Nico leads the others to the House of Hades.