Harry Potter started out as any other boy. He grew up with his two parents who adored him- James Potter and Lily Potter nee Evan. He lived in Godric's Hollow. A prophecy was made that he would destroy the dark lord, forcing him and his family to go into hiding under the fidelius charm, the secret keeper Peter Pettigrew (See The Marauders: A Biography). Then one fateful night- Halloween 1981- changed it all for him.

It turns out Peter Pettigrew betrayed the Potter family to Lord Voldemort, contrary to popular belief. The Dark Lord broke into the Potter family's house. Though only Harry knows exactly what happened that night, we do know that after Voldemort had finished James and Lily off, he went for Harry. Unfortunately for him, the curse rebounded- leaving Voldemort almost completely destroyed. 

From there, Harry went to live with his only relatives- the Dursleys- Vernon and Petunia (Lily's sister), and their son, the same age as Harry, Dudley. He grew up unknowing of the wizarding world, though Petunia Dursley is rumored to have known of it but not shared.

It all changed the day he got his acceptance letter into Hogwarts School of Witchcraft and Wizardry.