The science of fantasy. The sylvan Horn.
(Note: This sentence appears to be a direct translation or possibly a title, as it remains largely unchanged in English. "Sylvan" means relating to woods or forests, and "horn" could refer to a musical instrument or a hunting horn, often depicted in fantasy contexts.)
If this is meant to be more fluidly rephrased in English, additional context might be needed. For now, it stays nearly identical.
If you'd like a more interpretive translation or adjustment for natural flow, let me know!