Complex sentence: Carewe produced "Resurrection" (1927), based on the novel by Leo Tolstoy, which was a box office hit; although Hollywood had already made three versions of the film, Carewe thought his version would be the best.
Split into simpler sentences: Carewe produced "Resurrection" (1927), based on the novel by Leo Tolstoy, which was a box office hit. Although in Hollywood had already been three versions of the film, Carewe thought his version would be the best.