Albus DumbledoreAlbus Percival Wulfric Brian Dumbledore is a fictional character of the Harry Potter fantasy book series written by J. K. Rowling. He is the headmaster of Hogwarts School of Witchcraft and Wizardry.
He is characterized as old, benevolent, and powerful. As such he resembles a stereotypical good wizard in the mould of Merlin or Gandalf. He is often sympathetic to Harry Potter's difficulties. He was also the only wizard that Lord Voldemort feared. Dumbledore is about 150 years old.
In the movie versions of Harry Potter and the Philosopher's Stone (2001) and Harry Potter and the Chamber of Secrets (2002), Dumbledore was played by Richard Harris. Harris' death meant that a replacement had to be found for the role. News reports have confirmed that in Harry Potter and the Prisoner of Azkaban (2004), Dumbledore will be played by Michael Gambon.
Albus Dumbledore has a brother called Aberforth who has been in trouble for practising inappropriate charms on a goat. Aberforth may be the bartender at the Hog's Head Inn in Hogsmeade.
When Dumbledore entered Hogwarts(about 140 years ago) he was sorted into Gryfindor. He later became the Transfiguration teacher at Hogwarts.
Warning: Wikipedia contains spoilers
In the early 1940s, the Chamber of Secrets was opened. When a student named Myrtle was killed, the school was almost closed. However, Tom Riddle accused Hagrid. Dumbledore was the only one who seemed to think Hagrid was innocent, and he convinced Headmaster Dippet to train Hagrid to be game keeper.
That year a werewolf named Remus Lupin came to Hogwarts. Most headmasters would never have allowed a werewolf into Hogwarts, but Dumbledore thought that as long as special precautions were taken, there was no reason why Lupin should not attend.
The 1970s were the dark years when Voldemort was in power. Voldemort was in fact none other than Tom Riddle, who had been a student of Dumbledore years before. Dumbledore was working tirelessly against Voldemort.
In 1980, Sybill Trelawney applied to become the new divination teacher. Dumbledore hired her when she made a prediction about Voldemort. Two prominent members of the Order of the Phoenix, Lily and James Potter, knew that Voldemort was after them.
Lily and James hid using the Fidelus Charm, but they were betrayed. However, somehow Voldemort's powers broke and Harry survived with only a scar on his forehead to show that Voldemort had attacked him. To keep Harry safe, Dumbledore placed him in the safe keeping of the Vernon and Petunia Dursley, his mother's family, as she had died to save him.
In the same year that Harry came to Hogwarts, Voldemort atempted to steal the Philosopher's stone, but failed. One year later, the Chamber of Secrets was opened again, and Harry and his friends revealed that Hagrid had not opened the Chamber of Secrets, it was Riddle himself. One year latter, the servent of Voldemort escaped, and the next year Voldemort rose again. Dumbledore re-founded the Order of the Pheonix.
Dumbledore was twice dismissed: During Harry's second year in Hogwarts, Lucius Malfoy "persuaded" the twelve conselers of the school to vote for is desmissal as more and mora attacks were occuring (remember, the basilisk was petrifying people en the school). In Harry's fifth year, Harry and some more students organised a club called "Dumbledore's Army". When Dolores Umbridge find it out, she managed to contact the ministry and they sacked him.
In that same year, the Ministry of Magic refused to believe that Voldemort was responsible, and orchestrated a smear campaign against Harry Potter. This failed, and minister Cornelius Fudge was forced to accept that Voldemort had returned. Then, Dumbledore retunr to his job as the Headmaster of Hogwarts.
See also: Harry Potter and the Philosopher's Stone