In 1911, at the age of nineteen, J. R. R. Tolkien embarked on an adventurous journey through the Swiss Alps; with a heavy pack, he hiked over many high passes. More than fifty years later, he mentioned in a letter to his son Michael that this trip had deeply affected him. Bilbo's journey in The Hobbit from Rivendell to the other side of the Misty Mountains, he said, was based on his own adventures in 1911.