- New research indicates that a play published in 1728 was written by William Shakespeare
- Scholar Lewis Theobald had passed the work off as his own
- Texas researchers used software to analyze and compare the language of the men
(CNN)"Hamlet." "Romeo and Juliet." "A Midsummer Night's Dream."
For centuries, these plays and three dozen more by William Shakespeare have formed history's most heralded literary canon.
But now they may have to make room for an addition to Shakespeare's famous oeuvre.
New research indicates that "Double Falsehood," a play first published in 1728 by Lewis Theobald, was actually written more than a century earlier by Shakespeare himself with help from his friend John Fletcher. The findings were published this week by two scholars who used computer software to analyze the writings of the three men and compare it with the language of the "newer" play.
"The match between the 'Double Falsehood' play and Shakespeare was a landslide. It was shockingly clear," said Ryan L. Boyd, a researcher at the University of Texas at Austin.
The study, co-authored by Boyd and UT colleague James W. Pennebaker, was published in the journal Psychological Science.
"There's very little wiggle room to interpret the numbers any differently."
Boyd said he and Pennebaker analyzed 33 plays by Shakespeare, nine by Fletcher and 12 by Theobald to create a "psychological signature" of each author based on word choices, phrase patterns and other factors.
They compared those profiles to the language in "Double Falsehood" and determined that the play's first half was almost entirely written by Shakespeare, though the second half appeared to be split evenly between Shakespeare and Fletcher.
Only tiny traces of Theobald's signature were found.
"We're certainly not suggesting that Theobald didn't make edits," Boyd told CNN. "But he clearly did not write it."
"Double Falsehood," also known as "The Distressed Lovers," is based on the "Cardenio" section of Don Quixote, the classic 17th-century novel by Miguel de Cervantes. Set in Spain, the play revolves around the romantic entanglements of two brothers: one virtuous, one sinful.
Theobald said he based the play on three original manuscripts he had discovered, all of them written by Shakespeare. But many scholars have long dismissed the play as a fake, suspecting that Theobald tried to pass the Bard's work off as his own.
Shakespeare, who died in 1616, wrote most of his published plays between 1590 and 1612.
British publishers Arden Shakespeare published "Double Falsehood" in 2010 -- for the first time in 250 years -- amid renewed claims by experts that it was Shakespeare's work.
But the new study by Boyd and Pennebaker, the first to analyze the writings from a psychological perspective, may settle the matter once and for all.
Shakespearean scholar Brean Hammond, professor of modern English literature at Nottingham University in the UK, praised the Texas study for its scientific approach.
Hammond said Boyd and Pennebaker "have got no dogs in the fight. They're not literary scholars, (so) their work could be seen as more objective than some of the literary studies."
Hammond studied "Double Falsehood's" authorship from a literary perspective five years ago and found Shakespeare's DNA evident in the play. But he doubts the new research will put the matter entirely to rest.
"Those people who don't believe the play was written by Shakespeare aren't going to just lay down and die," he said.