In 1922, Einstein was en route to Japan when the announcement came he would be awarded the 1921 Nobel prize in physics, Winner's Auctions and Exhibitions said.
Upon his arrival in Tokyo, he holed up in his hotel room trying to put his thoughts to paper.
When an attendant came to his room to make a delivery, Einstein found himself without any money for a tip.
Instead, he handed him a signed note with one sentence, written in German: "A calm and humble life will bring more happiness than the pursuit of success and the constant restlessness that comes with it."
According to the auction house, Einstein advised the bellboy to keep the note, saying that some day its value will surpass the amount of a standard tip.
Almost a 100 years later, Einstein was proven right after the bellboy's nephew contacted the auction house to put the note up for sale. The identity of the online buyer has not been revealed.