Final answer:
Franz Schubert was 18 years old when he composed Erlkönig. 'Erlkönig' is a powerful and dramatic composition based on the poem by Johann Wolfgang von Goethe, depicting the haunting encounter between a father and a supernatural creature.
Step-by-step explanation:
Franz Schubert was only 18 years old when he composed the famous song 'Erlkönig'.
He wrote the song in 1815, which was a part of his prolific years as a composer.
'Erlkönig' is a powerful and dramatic composition based on the poem by Johann Wolfgang von Goethe, depicting the haunting encounter between a father and a supernatural creature.