Why did Berlioz call his work a Fantasy-Symphony?

Berlioz called his work a Fantasy-Symphony because it deviates from traditional symphonic form, instead presenting a more imaginative and programmatic approach. The term "fantasy" reflects the work's narrative and emotional journey, inspired by Berlioz's unrequited love and personal experiences. It combines orchestral innovation with a vivid storyline, allowing for greater expressive freedom than a conventional symphony. This approach emphasizes the subjective and emotional aspects of the music, making it a pioneering piece in the Romantic repertoire.