A definitive timeline of every Harry Potter Horcrux
What does it mean to be immortal? To Voldemort, it's a power worth killing for—seven times over. His Horcruxes (magical objects that were used to conceal parts of his fractured soul, for the uninitiated) were first mentioned in Harry Potter and the Half-Blood Prince (when Harry sees Professor Slughorn's altered memory of a young Tom Riddle asking how a Horcrux might work), but they date back decades. Becoming the Dark Lord doesn't happen in a day, you know.
Dec. 31, 1926: Tom Marvolo Riddle is born at Wool's Orphanage in London. His father, Tom Riddle Sr. (a Muggle), had abandoned the family, and his mother, Merope Gaunt (a witch), died shortly after arriving at the orphanage.
June 13, 1942: Tom Riddle murders Myrtle Warren (a.k.a. Moaning Myrtle) in the first-floor girls' bathroom at Hogwarts School of Witchcraft and Wizardry, sending a piece of his soul into his diary. It becomes his first Horcrux.
August 1943: Tom Riddle murders his father at home in Little Hangleton, sending a piece of his soul into a ring formerly owned by Marvolo Gaunt, the younger Riddle's grandfather and a descendent of Salazar Slytherin himself. The ring becomes his second Horcrux.
Unknown date, 1946: Hepzibah Smith, a witch who claims to be a direct descendant of Helga Hufflepuff, befriends Tom Riddle during a visit to the dark magic shop Borgin and Burkes in Knockturn Alley. She makes the mistake of revealing that because of her penchant for collecting valuable antiques, she has come into the possession of Hufflepuff's cup and Salazar Slytherin's locket.
Unknown date, 1946: Tom Riddle murders Hepzibah Smith, sending a piece of his soul into Helga Hufflepuff's cup. It becomes the third Horcrux. (Riddle also steals the Slytherin locket.)
Unknown date between 1946 and 1979: Tom Riddle murders an unknown Muggle tramp in an unknown location, sending a piece of his soul into Salazar Slytherin's locket. It becomes his fourth Horcrux.
Unknown date between 1946 and 1979: While hiding out in a forest in Albania, Tom Riddle murders a local peasant and sends a piece of his soul into Rowena Ravenclaw's diadem (a.k.a. tiara). It becomes the fifth Horcrux.
July 31, 1980: Harry James Potter is born to Lily and James Potter in Godric's Hollow.
Oct. 31, 1981: Voldemort murders Lily and James Potter in Godric's Hollow and attempts to murder Harry. The dark wizard's soul fragments entirely, sending a piece of it into Harry, and creating a sixth Horcrux.
May 29, 1993: Harry Potter stabs a basilisk fang into Tom Riddle's diary inside the Chamber of Secrets—unknowingly destroying his first Horcrux.
Unknown date, 1994: Bertha Jorkins, an employee of the Ministry of Magic, is lured to the Albanian forest by Peter Pettigrew, where she is tortured for information on the Triwizard Tournament. The memory curse leaves her badly damaged, so Voldemort kills her, sending a piece of his soul into his snake, Nagini, and creating his seventh and final Horcrux.
July 1996: Albus Dumbledore destroys Marvolo Gaunt's ring with Godric Gryffindor's sword in his headmaster's office at Hogwarts.
Dec. 28, 1997: Ron Weasley destroys Salazar Slytherin's locket deep in the Forest of Dean, Gloucestershire, by stabbing it with Godric Gryffindor's sword.
May 2, 1998: The Battle of Hogwarts begins.
Hermione Granger and Ron Weasley destroy the Hufflepuff's cup Horcrux inside the Chamber of Secrets—Hermione giving it the fatal blow with a basilisk fang.
In the Harry Potter and the Deathly Hallows book, Vincent Crabbe inadvertently destroys Rowena Ravenclaw's diadem in the Room of Requirement via Fiendfyre. In the film version (Harry Potter and the Deathly Hallows: Part II), Harry stabs the diadem with a basilisk fang and then Ron kicks it into a Fiendfyre, which was started by Gregory Goyle, in the Room of Requirement.
Neville Longbottom beheads Nagini with Godric Gryffindor's sword on the front steps of Hogwarts, further weakening Voldemort.
Voldemort uses the Avada Kedavra curse on Harry Potter, which sends Harry into limbo, destroys the Horcrux, and allows Harry to kill Voldemort.