Duel between Albus Dumbledore and Gellert Grindelwald

The duel between Hogwarts Headmaster, Albus Dumbledore and Dark Wizard, Gellert Grindelwald took place some time before the events in the Harry Potter series.

Before the Duel
Decades before the legendary duel, Gellert Grindelward had come to Godric's Hollow to stay with his great aunt Bathilda Bagshot. He became friends with the seventeen year old Albus Dumbledore and they both became obsessed with the powerful objects known as the Deathly Hallows. This trio included the Elder Wand, Resurrection Stone and Invisibility Cloak.

The plans became more and more farfetched. Albus's younger brother Aberforth intervened and pointed out the impossibilities of the scheme. Gellert became quickly tempered and the tree began to Duel. Arianna Dumbledore was killed in the process.

The Duel
Grindelward had began to get powerful and was killing many. Soon, it was decided that Albus Dumbledore would be the only one able to stop him. Albus procastinated. He put off the encounter until it would seem to coawrdly to aviod any longer.

Albus won the duel and the World's most powerful Wand came to his allegiance.

Afterwards
Grindelward was captured and detained in Nurmengard, a prison that he himseld had constructed to hold his enemies. Grindelwald would be murdered by Lord Voldemort in 1998 and would die to protect the elder wand. it is believed he felt Remorse. Albus Dumbledore returned to his place in Hogwarts until his death in 1997.