Claims that someone other than William Shakespeare of Stratford-upon-Avon wrote the works traditionally attributed to him were first explicitly made in the 19th century. Many scholars consider that there is no evidence of his authorship ever being questioned prior to then. This conclusion is not accepted, however, by proponents of an alternative author, who discern veiled allusions in contemporary documents they construe as evidence that the works attributed to him were written by someone else, and that certain early 18th-century satirical and allegorical tracts contain similar hints., cited in ;

Throughout the 18th century, Shakespeare was described as a transcendent genius and by the beginning of the 19th century Bardolatry was in full swing. Uneasiness about the difference between Shakespeare's godlike reputation and the humdrum facts of his biography continued to emerge in the 19th century. In 1853, with help from Ralph Waldo Emerson, Delia Bacon, an American teacher and writer, travelled to Britain to research her belief that Shakespeare's works were written by a group of dissatisfied politicians, in order to communicate the advanced political and philosophical ideas of Francis Bacon (no relation). Later writers such as Ignatius Donnelly portrayed Francis Bacon as the sole author. After being proposed by James Greenstreet in 1891, it was the advocacy of Professor Abel Lefranc, a renowned authority on Renaissance literature, which in 1918 put William Stanley, 6th Earl of Derby in a prominent position as a candidate.

The poet and playwright Christopher Marlowe was first proposed as a member of a group theory by T.W. White in 1892. This theory was expanded in 1895 by Wilbur G. Zeigler, where he became the group's principal writer. Other short pieces supporting the Marlovian theory appeared in 1902, 1916 and 1923, but the first book to bring it to prominence was Calvin Hoffman's 1955 The Man Who Was Shakespeare.

In 1920, an English school-teacher, J. Thomas Looney, published Shakespeare Identified, proposing a new candidate for the authorship in Edward de Vere, 17th Earl of Oxford. This theory gained many notable advocates, including Sigmund Freud, and since the publication of Charlton Ogburn's The Mysterious William Shakespeare: the Myth and the Reality in 1984, the Oxfordian theory, boosted in part by the advocacy of several Supreme Court justices, and high-profile theatre professionals, has become the most popular alternative authorship theory.

Alleged early doubts

The overwhelming majority of mainstream Shakespeare scholars agree that Shakespeare's authorship was not questioned during his lifetime or for two centuries afterward. Jonathan Bate writes, "No one in Shakespeare's lifetime or the first two hundred years after his death expressed the slightest doubt about his authorship." Proponents of alternative authors, however, claim to find hidden or oblique expressions of doubt in the writings of Shakespeare's contemporaries and in later publications.

In the early 20th century, Walter Begley and Bertram G. Theobald claimed that Elizabethan satirists Joseph Hall and John Marston alluded to Francis Bacon as the true author of Venus and Adonis and The Rape of Lucrece by using the sobriquet "Labeo" in a series of poems published in 1597–8. They take this to be a coded reference to Bacon on the grounds that the name derives from Rome's most famous legal scholar, Marcus Labeo, with Bacon holding an equivalent position in Elizabethan England. Hall denigrates several poems by Labeo and states that he passes off criticism to "shift it to another's name". This is taken to imply that he published under a pseudonym. In the following year Marston used Bacon's Latin motto in a poem and seems to quote from Venus and Adonis, which he attributes to Labeo. Theobald argued that this confirmed that Hall's Labeo was known to be Bacon and that he wrote Venus and Adonis. Critics of this view argue that the name Labeo derives from Attius Labeo, a notoriously bad Roman poet, and that Hall's Labeo could refer to one of many poets of the time, or even be a composite figure, standing for the triumph of bad verse.A Davenport, The Poems of Joseph Hall, Liverpool University Press, 1949. Also, Marston's use of the Latin motto is a different poem from the one which alludes to Venus and Adonis. Only the latter uses the name Labeo, so there is no link between Labeo and Bacon.

In 1948 Charles Wisner Barrell argued that the "Envoy", or postscript, to Thomas Edward's poem Narcissus (1595) identified the Earl of Oxford as Shakespeare. The Envoy uses allegorical nicknames in praising several Elizabethan poets, among them "Adon". This is generally accepted to be an allusion to Shakespeare as the mythical Adonis from his poem Venus and Adonis. In the next stanzas, Edwards mentions a poet dressed "in purple robes", "whose power floweth far." Since purple is, among other things, a symbol of aristocracy, most scholars accept that he is discussing an unidentified aristocratic poet. Barrell argued that the stanzas about Adon and the anonymous aristocrat must be seen together. He stated that Edwards is revealing that Adon (Shakespeare) is really the Earl of Oxford, forced by the Queen to use a pseudonym.Barrell, Charles Wisner. “Oxford vs. Other ‘Claimants’ of the Edwards Shakespearean Honors, 1593” ; The Shakespeare Fellowship Quarterly (Summer 1948) Variations on Barrell's argument have been repeated by Diana Price and Roger Stritmatter. Brenda James and William D. Rubinstein argues that the same passage points to Sir Henry Neville. Mainstream scholars assert that Edwards is discussing two separate poets, and it has also been suggested that (as in the final stanzas of Venus and Adonis) the purple refers to blood, with which his garments are "distain'd", and that the poet could be Robert Southwell, under torture in the Tower of London.

Many other passages supposedly containing hidden references to one or another candidate have been identified. Oxfordian writers have found ciphers in the writings of Francis Meres.Robert Detobel, K.C. Ligon, "Francis Meres and the Earl of Oxford", Brief Chronicles: An Interdisciplinary Journal of Authorship Studies, 1: 1, 2009, pp. 97–108. Marlovian Peter Farey argues that the poem on Shakespeare's monument is a riddle asking who is "in this monument" with Shakespeare, the answer to which is "Christofer Marley", as Marlowe spelt his own name.Peter Farey, "The Stratford Monument: A Riddle and Its Solution", Journal of the Open University Shakespeare Society, 12: 3, 2001, pp. 62-74.

Various anti-Stratfordian writers have interpreted poems by Ben Jonson, including his prefatory poem to the First Folio, as oblique references to Shakespeare's identity as a frontman for another writer. They have also identified him with such literary characters as the laughingstock Sogliardo in Jonson's Every Man Out of His Humour, the literary thief poet-ape in Jonson's poem of the same name, and the foolish poetry-lover Gullio in the university play The Return from Parnassus. Such characters are taken as evidence that the London theatrical world knew Shakespeare was a mere front for an unnamed author whose identity could not be explicitly given.

Visual imagery, including the Droeshout portrait has also been claimed to contain hidden messages.Marjorie B. Garber, Profiling Shakespeare, Taylor & Francis, 24 Mar 2008, p. 221. Edwin Durning-Lawrence asserts that "there is no question – there can be no possible question – that in fact it is a cunningly drawn cryptographic picture, shewing two left arms and a mask ... Especially note that the ear is a mask ear and stands out curiously; note also how distinct the line shewing the edge of the mask appears." Durning-Lawrence also claims that other engravings by Droeshout "may be similarly correctly characterised as cunningly composed, in order to reveal the true facts of the authorship of such works, unto those who were capable of grasping the hidden meaning of his engravings."Edwin Durning-Lawrence, Bacon Is Shake-Speare, John McBride Co., New York, 1910, pp. 23, 79–80. R.C. Churchill notes that Baconians have often claimed to find secret meanings in the imagery of the title pages and frontispieces of 17th-century books, such as the 1624 book Cryptomenytices et Cryptographiae, by Gustavus Selenus (a pseudonym of the Duke of Brunswick), or the 1632 edition of Florio's translation of Montaigne.

Alleged 18th-century allusions R. C. Churchill says that the first documented expression of doubt about Shakespeare's authorship came in 1760, in a farce entitled High Life Below Stairs in which a Miss Kitty poses the question: "Who wrote Shakespeare?" The Duke responds "Ben Jonson." Lady Bab then cries; "Oh, no! Shakespeare was written by one Mr. Finis, for I saw his name at the end of the book." Churchill writes that, while not a very "profound" joke, there "must have been, in the mid-eighteenth century, a certain amount of discussion as to the authenticity of the traditional authorship of Shakespeare, and the substitution of Ben Jonson is significant."Churchill, Shakespeare and His Betters, 1959, Indiana University Press, pp. 29–31.

George McMichael and Edward Glenn, summarising the views of doubters, quote passages in some early 18th-century satirical and allegorical works that were later identified by anti-Stratfordians as expressing authorship doubts. In a passage in An Essay Against Too Much Reading (1728) possibly written by Matthew Concanen, Shakespeare is described as "no Scholar, no Grammarian, no Historian, and in all probability cou'd not write English" and someone who uses an historian as a collaborator. The book also says that 'instead of Reading, he [Shakespeare] stuck close to Writing and Study without Book". Again, in The Life and Adventures of Common Sense: An Historical Allegory (1769) by Herbert Lawrence, the narrator, "Common Sense", portrays Shakespeare as a thief who stole a commonplace book containing "an infinite variety of Modes and Forms to express all the different sentiments of the human mind" from his father, "Wit" and his half-brother, "Humour". He also stole a magical glass created by "Genius", which allowed him to "penetrate into the deep recesses of the Soul of Man".Herbert Lawrence, The life and adventures of common sense: an historical allegory, Montagu Lawrence, 1769, pp. 147-48. He used these to write his plays. Thirdly, in a possible allusion to Bacon, The Story of the Learned Pig, By an officer of the Royal Navy (1786) is a tale of a soul that has successively migrated from the body of Romulus into various humans and animals, and is currently residing in The Learned Pig, a famous performing pig at the time that was the subject of much satirical literature. He recalls a previous pre-swinish incarnation in which he was a person called "Pimping Billy", who worked as a horse-holder at the playhouse with Shakespeare and was the real author of 5 of the plays.

Shakespearean scholars have seen nothing in these works to suggest genuine doubts about Shakespeare's authorship, since they are all presented as comic fantasies. The scene from High Life Below Stairs simply ridicules the stupidity of the characters, as Samuel Schoenbaum notes, adding that, "the Baconians, who discern in Townley's farce an early manifestation of the anti-Stratfordian creed, have never been remarkable for their sense of humour". Of the three booklets mentioned, the first two explicitly assert that Shakespeare wrote the works, albeit with assistance from a historian in the first, and magical aids in the second. The third does say that "Billy" was the real author of Hamlet, Othello, As You Like It and A Midsummer Night's Dream, but it also claims that he participated in numerous other historical events. Michael Dobson takes Pimping Billy to be a joke about Ben Jonson, since he is said to be the son of a character in Jonson's play Every Man in his Humour.