Dumbledore left Hogwarts in the 6th film half blood prince got killed by Snape, But the actor Michael Gambon returned in the 7th film the deathly hallows in his grave when Lord Voldermort open'd his grave to get the elder wond that belonged to Dumbledore so that's when dumbledore left and returned :).
Dumbledore.
The school's Head Master
It doesn't stand for anything. It's the name of the headmaster of Hogwarts, Albus DUMBLEDORE.
Slughorn was reluctant to work at Hogwarts; Harry helped Dumbledore convince Slughorn that it was in his (Slughorn's) best interest to do so - as Dumbledore had evidently foreseen. Apparently the main reason Dumbledore wanted Slughorn in Hogwarts is because Slughorn had some important information (which he really preferred to keep secret), which Harry and Dumbledore needed to defeat Lord Voldemort.Slughorn was reluctant to work at Hogwarts; Harry helped Dumbledore convince Slughorn that it was in his (Slughorn's) best interest to do so - as Dumbledore had evidently foreseen. Apparently the main reason Dumbledore wanted Slughorn in Hogwarts is because Slughorn had some important information (which he really preferred to keep secret), which Harry and Dumbledore needed to defeat Lord Voldemort.Slughorn was reluctant to work at Hogwarts; Harry helped Dumbledore convince Slughorn that it was in his (Slughorn's) best interest to do so - as Dumbledore had evidently foreseen. Apparently the main reason Dumbledore wanted Slughorn in Hogwarts is because Slughorn had some important information (which he really preferred to keep secret), which Harry and Dumbledore needed to defeat Lord Voldemort.Slughorn was reluctant to work at Hogwarts; Harry helped Dumbledore convince Slughorn that it was in his (Slughorn's) best interest to do so - as Dumbledore had evidently foreseen. Apparently the main reason Dumbledore wanted Slughorn in Hogwarts is because Slughorn had some important information (which he really preferred to keep secret), which Harry and Dumbledore needed to defeat Lord Voldemort.
i think it was grifinndor dumbledore was in it
well..he used to be the transfiguration teacher at Hogwarts...
albus percival wulfric brian dumbledore
Severus Snape
In the second book when Dumbledore has to leave for a while she steps up to the plate. Dumbledore comes back and is headmaster until he gets killed by Snape and again she becomes headmaster.
The Hogwarts headmaster (Harry Potter books and films) is "Professor Albus Percival Wulfric Brian Dumbledore."
Dolores Umbridge "tries to fire Proffessor Trelawney, but is stopped from making her leave Hogwarts completely by Albus Dumbledore "You may have the right to fire my teachers, but you do not have the right to banish them from the grounds".So Trelawyney was fired, but still allowed to live at Hogwarts, thanks to Dumbledore
Dumbledore, because he used to be a teacher (before Harry went to Hogwarts) but then got promoted to Headmaster.