He was an important writer of the 16th century, but Robert Greene is remembered today for just two words: "upstart crow". It was not his only sneering dismissal of William Shakespeare. He even suggested that his young contemporary was a plagiarist, in writing that he had "beautified himself in others' feathers". Having been mocked in Ben Elton's sitcom Upstart Crow, starring David Mitchell as Shakespeare, Greene can now feel some poetic justice as research has attributed to him a play - a revenge tragedy, no less - that appeared under Shakespeare's name in the Third and Fourth Folios. Complex linguistic analysis by Darren Freebury-Jones, a lecturer at the Shakespeare Birthplace Trust in Stratford-upon-Avon, has led him to conclude that Greene is the likely author of The Lamentable Tragedy of Locrine. He said of it: "That play fits into the expectations for Greene's prosodic, linguistic and phraseological habits in almost every respect." Published in 1595, the play is about the mythical founders of Britain, an ailing King Brutus and his son Locrine, whom he describes in Act I as "the columne of my familie,/And onely piller of my weakned age". Its title page stated that it was "newly set forth, overseen and corrected, By W.S" - initials that had suggested Shakespeare's involvement. The play was included in Shakespeare's 1664 Third Folio, of which the trust has one of the few surviving copies, and the 1685 Fourth Folio. It was described by the eminent scholar Edmond Malone in 1778 as one of his early works. Another academic, Peter Kirwan - in a 2015 study for Cambridge University Press - raised "the possibility of Shakespeare's contribution" to Locrine. Others have singled out Greene and George Peele, suggested as Shakespeare's co-author on Titus Andronicus, among 16th-century authorship candidates, but Dr Freebury-Jones's study is the most rigorous attempt ever undertaken to determine the scope of Greene's dramatic canon. Using an electronic database called "Collocations and N-grams", which contains the texts of 527 plays dating from 1552 to 1657, he discovered "little to no linguistic commonality" between Locrine and Shakespeare's plays, while "Greene shared more unique ... phrases with the play, such as 'with silver stream' and 'thunder forth revenge', than other authorial suspects". Dr Freebury-Jones examined Greene's verse style, analysing word combinations and linguistic quirks characteristic of him, such as the frequency of his use of metrical line fillers - notably "for to" and "like to" (meaning "like"). The research will appear in the peer-reviewed academic journal Style, to be published by Penn State University Press next month.