2. The Sorrows of Young Werther (1774)
Author: Johann Wolfgang Von Goethe
The Sorrows of Young Werther catapulted Goethe to an insane level of literary celebrity. The story of unrequited love, which the kids today might find "quite emo," didn't sit well with Goethe as he grew older, however. He regretted the sentimentality of the piece and he also regretted revealing his own unrequited love to the world.
Nonetheless, even in his last years, he was best remembered for Werther. The autobiographical novel was so popular when it was released that lovelorn young men dressed like the protagonist and even [SPOILER ALERT] took their lives in the same fashion as desperate young Werther. We're lucky that Goethe isn't writing today, as there would certainly be a good number of young folks running around in "Team Werther" T-shirts.