New research suggests Edward III was 'beyond any reasonable doubt' written by William Shakespeare

While historians long agreed Shakespeare wrote at least a few scenes for the play, new computerised textual analysis suggested the Stratford-born playwright was the principal writer, with Marlowe as a major collaborator.

Literary scholars said the new research has "massive implications for our understanding of the relationship" between the two men.

The researchers used multiple forms of computerised linguistic analysis, breaking the play into segments and comparing them with securely attributed works by 10 professional playwrights active from the late 1580s to the mid-1590s.

Their method examined features such as word frequency and the spacing between terms within sentences.

Dr Rory Loughnane, who pioneered the research, told The Guardian: "That’s the new finding, both Shakespeare, now confirmed beyond doubt, and Marlowe, unexpectedly found for the first time, are present in the play, and therefore it represents a newly found collaboration between the two.

“It has massive implications for our understanding of the relationship between the two most important dramatists of this period.

"This changes both the Shakespeare canon and the Marlowe canon and will be of significant international interest."

Their research identified certain "marker" words that proved particularly telling; "martial," for instance, appears regularly in Marlowe's dramatic output but rarely in the writing of his contemporaries.

Of the play's segments, 23, described as "the lion's share", were classified as Shakespeare's work, whilst nine were attributed to Marlowe.

The analysis confirms that the Countess scenes, among other passages, bear Shakespeare's distinctive linguistic fingerprint.

Marlowe's contribution, meanwhile, appears in the play's closing episodes, particularly those depicting the seizure of King Jean and Prince Charles and the mass capitulation of the French at Calais.

Rather than relying on any single piece of evidence, the researchers drew on multiple analytical approaches that examined distinct aspects of the text.

Prof Greatley-Hirsch told the Guardian: "What makes the evidence particularly compelling is that we're not relying on a single verbal parallel or statistical test.

Different forms of analysis, looking at different features of the language, appear to repeatedly distinguish Marlowe's writing from Shakespeare's within the play."

The findings reshape scholarly understanding of how the two greatest dramatists of the Elizabethan age related to one another.

Born just weeks apart, Shakespeare and Marlowe have traditionally been cast as fierce competitors forging their reputations in the same theatrical world.

A 2016 study had already identified Marlowe as a co-author of the three Henry VI plays, and this latest research, dating their work on Edward III to around 1592, points to a deeper creative partnership during their mid-to-late twenties.

Dr Loughnane said: "The discovery helps us see young Shakespeare differently. The Shakespeare of the early 1590s was not yet the solitary national genius constructed by later generations."

Marlowe's death at just 29, following a brawl in a lodging house in 1593, brought what Dr Loughnane described as "a fruitful early career series of collaborations" to an abrupt end.

The research will be published in the journal Shakespeare Quarterly in November.

Dr Loughnane's new book, Shakespeare at Thirty, is due out this week and offers further insights into the playwright's formative years.

He said: "It has massive implications for our understanding of the relationship between the two most important dramatists of this period.

"This changes both the Shakespeare canon and the Marlowe canon."