The Bixby letter is one of the most famous letters sent by Abraham Lincoln. It's a brief letter of consolation sent from the President to Lydia Parker Bixby, a widow who lost five sons in the Union Army during the American Civil War.
The letter reads as a personal condolence to Lydia, and has been praised as some of Lincoln's finest work. However new analysis has found that the letter probably wasn't written by Lincoln at all.
Using the same technique that outed JK Rowling as the author of the Robert Galbraith novels, and identified the creator of Bitcoin, researchers say that they have solved the mystery of who wrote the letter.
A team from the Center for Forensic Linguistics at Aston University think they can prove the letter was in fact written by Lincoln's secretary, John Hay. They conclude that the letter almost certainly wasn't authored by Lincoln, despite the original letter being lost and unavailable for analysis.
The research, submitted to the journal Digital Scholarship in the Humanities, used n-gram tracing to discover the origin of the letter. This involves using computer software to analyze texts from authors. The program traces out sequences of linguistic forms in the writing. Each author has their own distinctive patterns, which the program can then look for when analyzing other texts, to see if they are from the same author.
The researchers used the tool to analyze 500 confirmed texts from Hay and a large sample of Lincoln's writings to see their linguistic patterns. After doing this, they then put the short letter in for analysis, to see who it matched most closely to.
“Nearly 90 percent of the time, the method identified Hay as the author of the letter, with the analysis being inconclusive in the rest of the cases,” the team explained in a statement.
The team, which included the University of Manchester's Dr Andrea Nini, created a whole new method in order to be able to analyze shorter texts.
"We believe that this new method can now be also successfully applied to other cases," Dr Nini said. "Especially present-day forensic cases involving short, threatening or malicious texts."
Dr Nini is now hoping to use this new method to solve the mystery of Jack the Ripper by analyzing letters allegedly written by the murderer.