If the Party could thrust its hand into the past and say of this or that event, it never happened — that, surely, was more terrifying than mere torture and death? 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.”

George Orwell (1903-1950) English writer [pseud. of Eric Arthur Blair]

Nineteen Eighty-Four (1949)
    (Source)

Sometimes paraphrased, "He who controls the past controls the future. He who controls the present controls the past."