Albert Einstein's Handwritten Letter Featuring E = mc2 Equation Sells For $1.2 Million at Auction

A handwritten letter from theoretical physicist Albert Einstein featuring his famous E = mc2 equation has sold for over $1.2 million at an auction.

Boston-based auction house RR Auction revealed on Friday the auction had closed with a winning bid of $1,243,707, a considerably higher figure than what was expected. Associated Pressreports that Bobby Livingston, executive vice president at the auction house, said it was expected to sell for somewhere closer to $400,000. Archivists from the Einstein Papers Project and the Hebrew University of Jerusalem suggest there's only three other known examples of Einstein's revolutionary equation in his handwriting.

"It’s an important letter from both a holographic and a physics point of view," said Livingston. The letter itself, which is in German, is dated Oct. 26, 1946. It was addressed to Polish American physicist Ludwik Silberstein, who had been known as a critic of some of Einstein’s work. “Your question can be answered from the E=mc2 formula, without any erudition," a translation of Einstein's letter reads. Due to the level of rarity of the letter, sold by one of Silberstein’s descendants from his personal archives, the item was the subject of a bidding war.

The identity of the buyer was not made public, but Livingston did say it was between them and one other party by the time bidding reached $700,000. Initially, there was aggressive bidding between five parties, Livingston said. The equation has often been called the most famous equation in the world. Bidding started on May 13, and came to an end on Thursday.