Excerpts from Books and Wikipedia
"Identified with anti-clerical, liberal opinion, Zola's open letter to President Felix Faure accused leading army officers of engaging in a conspiracy to convict Alfred Dreyfus, a Jewish staff officer, of espionage for Germany; sending the innocent man to Devil's Island penal colony; and then deliberately covering up their crimes. The letter was the catalyst that blew the Dreyfus Affair open and triggered the long process of judicial revision that eventually--despite internal divisions and the fall of several governments--resulted in Dreyfus's exoneration and the exposure of Esterhazy, the real spy, whom France's conservative military and clerical establishment had combined to protect. The letter had appalling personal consequences for Zola. In 1899 he was convicted of defamation and was forced to flee to London to escape jail. He spent a year there in exile with his mistress and children before the growing evidence of Dreyfus's innocence allowed him to return. In Zola's words, 'Truth is on the march and nothing can stop it.' . . . In 1908 after Dreyfus had finally been reinstated in the army, Zola's remains were transferred to the Pantheon in Paris, where France's greatest heroes are honored." [Furtado: 1001 Days]