context: In an attempt to convince journalist Alan Foster [Anthony Franciosa] that his horror
  stories are not pure fantasy, Edgar Allan Poe [Klaus Kinski] challenges the journalist to
  spend All Soul's Eve in Lord Thomas Blackwood's [Enrico Osterman] mansion, a challenge from
  which no one has ever returned. Alan's evening in the uninhabited,
  spiderweb-invested castle starts out uneventfully, until Alan discovers
  that he is not alone. Sharing the house with him is Elisabeth Blackwood [Michèle Mercier],
  sister of Lord Blackwell and the most beautiful woman he has ever seen,
  along with Elisabeth's lover Julia [Karin Field], a murderer named Herbert [Raf Baldassarre], one Dr
  Carmus [Peter Carsten] who writes books about metaphysical medicine, and an entire
  ballroom full of dancers.Within 15 minutes, Alan and Elisabeth have fallen in love, but it is
  Dr Carmas who explains the scene that begins to unfold before them. While
  Elisabeth's husband William [Silvano Tranquilli] was away on business, Elisabeth took up with
  Herbert. Upon William's return, Herbert stabbed him in a jealous rage.
  When Herbert turned on Elisabeth, Julia killed Herbert. Elisabeth then
  killed Julia in revenge. Yet, there they all are, alive and Well.It's like a snake, Carmus explains, that will continue to bite even
  after having its head separated from its body, because its sense of
  defense does not die when the body dies. The soul and the senses can
  continue to live on, even when the body has passed and begins to
  disintegrate. Now, each year on All Soul's Eve, the dead ones come to life
  in search of human blood to tide them over another year.Suddenly all the players begin advancing on Alan. "We need your
  blood," says Carmus. "Your blood is our life," says Julia. "It's the only
  way to assure us a night of life one year from now." Alan tries to escape
  but all the doors are locked. Out of love for him, Elisabeth offers to
  help Alan escape. She leads him out to the front gate but, being dead, she
  can go no further. Alan tries to pull her with him, but she disappears. As
  Alan goes through the front gate, he is impaled on a wrought iron spike.Epilogue: Poe and Lord Blackwood ride by the gate in their carriage.
  Seeing Alan impaled on the gate, Lord Blackwood pronounces him the loser
  of the wager. Elisabeth's voice is heard asking Alan whether he stayed for
  her, and Alan replies, "Yes, Elisabeth." [Original Synopsis by bj_kuehl.]
question: Who is the journalist who challenged Poe on the authenticity of his stories?
answer: Alan Foster