 Diderot’s public intellectual acclaim increased with each of these books, and by the time of the Lettre sur les aveugles he had become famous enough for Voltaire himself, already the public face of radical philosophie, to write to Diderot praising his books. But the same acclaim that attracted Voltaire’s attention also rendered Diderot suspicious in the eyes of the French authorities. A police file with Diderot’s name on it was opened soon after the Pensées philosophiques appeared, and this work was ordered to be publicly burned in July 1746. By 1749, the evidence pointing to Diderot’s authorship of these subversive (potentially or explicitly atheistic) works was conclusive, and after the publication of the Lettre sur les aveugles an order was issued ordering Diderot’s incarceration in Vincennes prison. He was imprisoned for three months starting in July 1749, before being released the following November.