Oceania has always been at war with Eurasia

From George Orwell's '1984':

...The Party said that Oceania had never been in alliance with Eurasia. He, Winston Smith, knew that Oceania had been in alliance with Eurasia as short a time as four years ago. But where did that knowledge exist? Only in his own consciousness, which in any case, must soon be annihilated. And if all others accepted the lie which the Party imposed - if all records told the same tale - then the lie passed into history and became truth. ‘Who controls the past,’ ran the Party slogan, ‘controls the future: who controls the present controls the past’. And yet the past, though of its nature alterable, never had been altered. Whatever was true now was true from everlasting to everlasting. It was quite simple. All that was needed was an unending series of victories over your own memory. ‘Reality control’, they called it - in Newspeak, ‘doublethink.’

"Stand easy!" barked the instructress, a little more genially.

Winston stood, his arms to his side, and slowly refilled his lungs with air. His mind slid away from the labyrinthine world of doublethink. To know and not to know, to be conscious of complete truthfulness while telling carefully constructed lies, to hold simultaneously two opinions which cancelled out, knowing them to be contradictory and believing in both of them, to use logic against logic, to repudiate morality while laying claim to it, to believe that democracy was impossible ilk and that the Party was the guardian of democracy, to forget whatever it was necessary to forget, then draw it back into memory again at the moment it was needed, then, promptly to forget it again, and above all, to apply the same process to the process itself - that was the ultimate subtlety: consciously to induce unconsciousness, and then, once again, to become unconscious of the act of hypnosis you had just performed. Even to understand the word ‘doublethink’ involved the use of doublethink...