Albus Percieval Wulfric Brian Dumbledore

The acknowledged most powerful wizard in England, if not all Europe and beyond, Defeater of Grindelwald, Headmaster of Hogwarts, Chief Mugwump and more, this wizard is known for an incredible number of titles and abilities
Born in a time when Light and Dark opposed each other with passion, Albus Dumbledore ignored politics in favor of learning. His gift for absorbing knowledge grew at a rate eclipsing his power as a wizard, a fact which was not noticed by the public at large.
During the conflict known as World War Two, Dumbledore emerged from seclusion, and challenged the Dark Lord Grindelwald for control. Defeating the Dark Lord granted him political clout far above expectation, catapulting him from a humble educator into the public arena. As always he preferred to remain a teacher, and became Headmaster of Hogwarts.
He has held that position for what is now considered to be the longest tenure in many generations, outlasting past Headmasters by decades. At the same time he has retained power in other arenas, serving as political impetus for the Light and opposing the Dark.

First Timeline:

Dumbledore, knowing the full Prophecy, ensures Harry is sent to Azkaban to stay safe from Voldemort. After his untimely death, John Potter decides to leave his brother in Azkaban.

Second Timeline:

In a repeat of the first timeline, Dumbledore again leaves Harry in Azkaban and dies before releasing him.

Third Timeline:

Early Years: It is known that Albus Dumbledore was friends with Gellart Grindlewald. A Ritual the two engaged upon what is known as the Unforgivable Ritual.

Pre-First Year:
Harry is moved to the Dursleys under Dumbledore's guidance. Following the infiltration of his office at Hogwarts by Lord Slytherin, Dumbledore revised the protections around the Philosopher's Stone (aka Sorcerer's Stone), making it a series of layers including a VCR programming phase, the Fidelius, and re-directional charms.
First Year: Upon Harry's arrival at Hogwarts, Dumbledore realizes something is wrong, and begins to determine corrective measures. During the events of Book 1, Dumbledore calls for a lockdown of Hogwarts, summoning Aurors from the Ministry twice.
In Harry's duelling competition, Dumbledore elects to take advantage of the opportunity to put Harry out of play. As Harry is the true subject to the Prophecy, Dumbledore believes that Harry should be removed from society, for both his and the Wizarding World's protection. Therefore, he concocts a plan to frame Harry for injuring his brother, and thus subject to trial and be sent to Azkaban.
Harry declines signing an admission of guilt, and goes to court. His team, including the Greengrass Family and the Lovegood Family use acquired minor Favors with the Bones family, to ensure a fair trial. After this trial reaches conclusion (during which Harry manages to acquire one of Dumbledore's hairs), Harry is declared not guilty and set free.

Affiliated with the Light political party, often considered its leader, Dumbledore has ensured a bright future for Britain these many decades. Albus Dumbledore initiated a Ritual during World War Two, in order to defeat Dark Lords. It is believed that this ritual sacrificed a sense of restraint when it came to stopping potential Dark Lords.