If Voldemort knew Harry was a horcrux he probably would've either convinced Harry to become a
Voldemort wasn't aware of Harry being a pseudo-horcrux because he didn't plan it, and Harry didn't know either until Voldemort “killed” him, but he actually killed the piece of soul kept in him.
Dumbledore knew that destroying Voldemort's horcruxes was the only way to truly defeat him. He believed that Harry was the one person who was smart, courageous, and perhaps lucky enough to find and eliminate all the horcruxes.
If a witch or wizard creates a Horcrux, then they can never truly die until said Horcrux is destroyed as well. A person's physical body can be destroyed, but their soul can live on. So, when Voldemort's killing curse backfired after attempting to murder young Harry, his physical body was destroyed.
It would also explain why Snape saved Harry's life in the Harry Potter and the Sorcerer's Stone,45 and why he tried to save it again in Harry Potter and the Prisoner of Azkaban:46 As long as Harry was alive and Snape was the only one who knew Harry was a Horcrux, Snape would have leverage over Voldemort if ever ...
Voldemort intentionally made six Horcruxes, but when he used Avada Kedavra on Harry, he unintentionally created a seventh Horcrux. Instead of dying, Lily's love for Harry created a counter 'curse' known as Sacrificial Protection and saved Harry.
He does not find out when he realizes Harry's scar first starts hurting him. Dumbledore and Harry do not really talk about the pain Harry experiences in his scar until the later books, but it's sort of generally accepted that Dumbledore knows about it.
The three Deathly Hallows – the Invisibility Cloak, the Resurrection Stone and the Elder Wand – have tempted many a wizard over the years.
Harry eventually comes to possess all three Hallows – the cloak being inherited from his father James Potter, later understood to be a descendant of one of the Peverell brothers, the Resurrection Stone in the Golden Snitch bequeathed to him by Dumbledore, and the allegiance and mastery of the Elder Wand when he defeats ...
Because it was futile and quite impossible to do so effectively. They didn't know where they had to go.
“Dumbledore didn't want to lose his wand at that point and Draco disarmed him. So that meant that the wand gave Draco its allegiance, even though Draco never knew it, even though Draco never touched it. “From that moment on, that wand gave its allegiance to Draco, and it wouldn't work as well for anyone but Draco.”
On destroying Horcruxes
Of course, the ever-wise Rowling was able to shed some light on the matter. “A Horcrux can only be destroyed if its container is damaged beyond repair, Harry was healed by Fawkes,” she wrote, referencing Dumbledore's beloved phoenix. “Had he died, the Horcrux would indeed have been destroyed.”
So why wasn't the Horcrux residing in Harry's head destroyed when he was bitten by the Basilisk? The answer is simple: He didn't actually die. Fawkes quickly healed the bite wound with his phoenix tears just in time. Case closed.
The clue he received in the film was from Bellatrix, who was in a frantic frenzy when she thought her vault was broken into. He is ultimately able to identify the cup as a Horcrux because of his ability to hear the piece of Voldemort's soul contained within them, an ability which is not present in the books.
Voldemort was scared it had gone wrong and was nervous to check. It was only when Narcissa checked that his arrogance returned. Only then he made up lies about Harry running despite all DE and Hagrid knowing that wasn't true.
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).
James inherited the cloak from his father, Fleamont Potter, who inherited it as a descendant of Iolanthe Peverell -- a granddaughter of Ignotus Peverell. The cloak passed down through generations of the family until it reached James and then Harry.
Draco Malfoy's mother Narcissa was cold, cunning and devoted to the Dark Lord. But she was also a mother, which meant she was willing to risk everything to make sure her son was safe. When Harry survived Voldemort's Killing Curse for the second time, Narcissa pretended he was dead so she could get to Draco.
Where did James Potter get the invisibility cloak from? The Invisibility Cloak originated from Ignotus Peverell, James' ascendant. The Cloak was passed from father to son, mother to daughter, through the centuries until James received the Cloak from his own father.
At different points, Dumbledore possessed all three Deathly Hallows. He won the Elder Wand from Grindelwald, had the Invisibility Cloak in his possession when James Potter died, and wore the Resurrection Stone as it sat in Marvolo Gaunt's ring. Dumbledore's powers are really quite extraordinary!
Additionally, in Harry Potter and the Chamber of Secrets, Professor Dumbledore looks right at Harry and Ron underneath the Invisibility Cloak while in Hagrid's hut, suggesting that Dumbledore might actually be able to see through the Invisibility Cloak.
In a chat with fans on the-leaky-cauldron.org, J. K. Rowling answered a fan's question of why Albus Dumbledore was sometimes able to see Harry under the Cloak of Invisibility, explaining that he used the Human-presence-revealing spell with non-verbal magic.
She noticed how Harry acted more like Voldemort when the locker was on, while Ron had acted insecure and her emotional. She knew that something was off and at that point it was in her head that he was a horcrux.
Dumbledore knew Harry and Ron were under the invisibility cloak at Hagrid's hut in Harry Potter and the Chamber of Secrets, as his eyes flickered in their direction.
Additionally, when Harry touches the ring, there is a flash of images as the ring reacts to him, which Dumbledore explains as an identifiable trace of lingering Dark magic.