The diary dates back to when Voldemort was still Tom Marvolo Riddle. After opening the Chamber of Secrets, he used the Basilisk to kill Myrtle Warren, providing the murder necessary to craft a Horcrux.
Voldemort entrusted his diary to Lucius Malfoy, who later seized the opportunity to smuggle it back into Hogwarts. Malfoy slipped the book to Ginny Weasley, who poured her heart and soul into its pages. Riddle’s spirit possessed Ginny and used her to reopen the Chamber, freeing Slytherin’s Basilisk to Petrify Argus Filch’s cat, Colin Creevey, Justin Finch-Fletchley, Nearly Headless Nick, Penelope Clearwater and Hermione Granger.
When a terrified Ginny attempted to dispose of the diary, it fell into the hands of Riddle’s future nemesis Harry Potter. Harry destroyed the diary with a Basilisk fang then used its remains to trick Lucius Malfoy into freeing Dobby.
The diary showed preserved memories, like a Pensieve, which included former Hogwarts headmaster Armando Dippet, a teenage Rubeus Hagrid, the infant Acromantula Aragog and a young(ish) Professor Albus Dumbledore. Another link to the past was Riddle’s victim Myrtle Warren, who never left Hogwarts and now lives her afterlife as Moaning Myrtle.
This Horcrux was intrinsically tied to Voldemort’s family. His father was its murder victim while his mother’s side provided the curious heirloom.
Riddle left Mrs Cole’s orphanage to attend Hogwarts, yet this new magical life could not end the resentment he harboured towards his parents. As a teenager, Voldemort travelled to his mother’s former home and met his uncle, Morfin Gaunt, who was wearing the family ring. The ring already had a remarkable history as it contained the Resurrection Stone, owned by Cadmus Peverell and immortalised in ‘The Tale of the Three Brothers’. Ironically this fable warns of the folly in trying to cheat death and Voldemort used Horcruxes to do exactly that.
On learning his father’s location Voldemort murdered Tom Riddle Sr, as well as his own grandparents for good measure. Morfin was left with a false memory that caused him to confess to murders he didn’t commit, and a stint in Azkaban for his troubles. In the Muggle world the Riddles’ gardener Frank Bryce was suspected. The ring went missing, but a Pensieve memory showed Voldemort wearing it while questioning Horace Slughorn about multiple Horcruxes.
The ring was eventually destroyed by Albus Dumbledore, but that came at a price. Recognising the stone and tempted to see his parents and sister again, Dumbledore fell victim to a powerful curse that was partially contained by Severus Snape. The stone, now defunct as a Horcrux, was placed inside a Snitch and passed to Harry by Rufus Scrimgeour. It was last used to recall Lily and James Potter, Sirius Black and Remus Lupin as Harry prepared to face death.
When Voldemort searched for items from the Hogwarts founders, two appeared at once – Helga Hufflepuff’s cup and Salazar Slytherin’s locket.
A portrait over the wooden mantelpiece (carved all over with decorative dancing badgers) shows Helga Hufflepuff, one of the four founders of Hogwarts School, toasting her students with a tiny, two-handled golden cup.
‘Hufflepuff Common Room’, Pottermore
This cup was handed down through Hufflepuff’s descendants until it reached Hepzibah Smith. The ageing witch took a shine to a young Borgin and Burkes clerk, treating him to a glimpse of her most treasured belongings. Two days later, Hepzibah was dead and her house-elf Hokey seemed to remember poisoning her mistress’s cocoa. The cup and locket had both vanished.
The cup, which was made a Horcrux with Hepzibah’s death, was left with Bellatrix Lestrange who kept it at Gringotts. Griphook and an Imperiused Bogrod helped Harry, Ron and Hermione break into Bellatrix’s vault and recover the Horcrux. The cup was destroyed by Hermione Granger, using a fang from the Basilisk’s corpse.
The locket was another prized possession of the Gaunt family.
Voldemort’s mother Merope stole the golden locket from her family home and fled to London, where she pawned it out of desperation. Eventually it made its way to Hepzibah Smith’s collection.
After robbing Hepzibah, Voldemort made another Horcrux by killing a homeless Muggle, then hid the locket in a remote cave protected by Dark magic and Inferi. Astonishingly its defences were breached twice: first by Kreacher and Regulus Black, then by Harry and Dumbledore who uncovered Regulus’s decoy.
The real Horcrux was taken to Twelve Grimmauld Place where Kreacher, following his master’s orders, tried to destroy it. When it went missing, Kreacher apprehended Mundungus Fletcher, who had stolen the locket and given it to Dolores Umbridge. Following a daring infiltration mission at the Ministry of Magic during Mary Cattermole’s trial, Harry – along with Ron (disguised as Mary’s husband, Reginald) and Hermione – retrieved the locket. It was finally destroyed by Ron Weasley, using Godric Gryffindor’s sword.
One person who might have known a thing or two about the diadem was Florean Fortescue, owner of Diagon Alley’s ice-cream parlour:
I imagined the historically-minded Florean might have a smattering of information on matters as diverse as the Elder Wand and the diadem of Ravenclaw.
‘Florean Fortescue’, Pottermore
Sadly we’ll never know, as Florean was abducted and killed during the Second Wizarding War. His is one of several ‘ghost plots’ that never made the final draft.
Voldemort used his talent for manipulation on the Grey Lady, Rowena Ravenclaw’s daughter Helena. This was no easy task as the Lady was a shy ghost reluctant to discuss such matters, yet Voldemort’s persuasion prevailed. It transpired that Helena had stolen her mother’s diadem and hidden it in Albania before being tracked down and fatally wounded. Helena’s killer then turned the weapon on himself, becoming the Bloody Baron of Slytherin.
Having coaxed out Helena’s secret, Voldemort travelled to Albania and retrieved the diadem, murdering a peasant to create the Horcrux. He took it to Hogwarts while inquiring about a teaching position and stored it in the Room of Requirement. Notable users of this room have included the members of Dumbledore’s Army and Draco Malfoy.
Bizarrely, the diadem was accidentally destroyed by the son of a Death Eater. Vincent Crabbe unleashed the powerful Fiendfyre Curse, which quickly blazed out of control – destroying both the diadem and Crabbe himself. Gregory Goyle and Draco escaped thanks to Harry, Ron and Hermione.
Voldemort used this vicious snake and the killing of Bertha Jorkins to create his final Horcrux.
As well as reinforcing connections to Salazar Slytherin, Nagini proved extremely useful. Wormtail milked her venom for Voldemort and she acted as sentry when they took refuge in the old Riddle house, alerting them to the presence of an eavesdropping Frank Bryce.
Nagini could attack Voldemort’s enemies such as Arthur Weasley, dispose of his victims (Charity Burbage) and threaten his followers, including Thorfinn Rowle. She was also used to lay a trap for Harry at Bathilda Bagshot’s house and to murder Severus Snape at the Battle of Hogwarts. During the battle, Nagini was beheaded by Neville Longbottom, using Gryffindor’s sword.
At Godric’s Hollow, Voldemort left Harry with more than a scar.
When Voldemort attempted to murder the infant, a piece of his maimed soul attached itself to Harry Potter. As a result, some of Voldemort’s thoughts and abilities were shared with him, until Harry was struck with the Avada Kedavra Curse.
To complete his collection, Voldemort sought to create a Horcrux with Gryffindor affiliations and – in Harry, who would be sorted into Gryffindor – effectively made one by mistake. Thanks to Harry’s actions, Godric Gryffindor’s sword became a weapon that could be used against the other Horcruxes. Voldemort’s failure to corrupt Harry, or the sword by making it a Horcrux, eventually spelled his downfall.
Though not a ‘true’ Horcrux, Quirrell did temporarily contain part of Voldemort’s soul. Unlike the other Horcruxes, the soul fragment escaped before the vessel was destroyed.