Felix Mendelssohn wrote his A Midsummer Night's Dream Overture when he was only 17, but he didn't finish the job until 16 years later…
Almost unbelievably, Felix Mendelssohn wrote this zipping overture when he was just 17 years old. The wunderkind was sure to include all sorts of special effects too - ones that are completely in keeping with Shakespeare's original play. So, you'll hear the scuttling feet of fairies as they scamper about the stage, and even the braying of poor Bottom, who is turned into an ass.
Legend has it that Mendelssohn had to battle through a ferocious snow storm to even attend the overture's premiere in 1827. It was his first public appearance, and surely marked the dawning of a major new musical talent in Europe. Even if he wasn't 17 years old when he wrote it, it's a remarkably sophisticated work - broadly romantic in sound, it actually adheres to a more old-fashioned, classical structure.
Strangely, it wasn't until 16 years later in 1842 that Mendelssohn wrote the incidental music for a production of the play, by which time you'd expect him to have evolved his compositional style somewhat. However, it's perfectly common to hear an orchestral suite of not only the Overture, but several highlights from the incidental music too.