In 1831 appeared his 3-volume History of English Dramatic Poetry to the Time of Shakespeare and Annals of the Stage to the Restoration,[4] a badly arranged but valuable work.

[5] It obtained for him the post of librarian to the 6th Duke of Devonshire,[6] and, subsequently, access to the chief collections of early English literature throughout the kingdom, especially to the treasures of Lord Ellesmere at Bridgewater House.

[15] Collier's friend Dyce was among the first to reject many of the alterations by the "Old Corrector" as "ignorant, tasteless and wanton", while recognizing that others required no more authority than common sense to be accepted as correct, many having been proposed already by other scholars.

Halliwell showed the Dulwich letter to have been (at best) misinterpreted by Collier, and stated (with the owner's permission) his misgivings that Lord Ellesmere's Shakespearean manuscripts were all modern forgeries.

[20] In response to these challenges, in January 1856 Collier made a legal affidavit swearing to the truth of his statements regarding the Coleridge lectures and the Perkins folio, and sought to move the Court of Queen's Bench for a criminal action for libel against the publisher John Russell Smith.

While Lord Campbell, presiding, refused to proceed, he commended the character of the applicant and pronounced him to be vindicated by his affidavit, and afterwards gave Collier other tokens of his friendship and esteem.

[22] Their friendship irrecoverably broken, Dyce responded in a full volume by rejecting Collier's charges against him as artful and deliberate misrepresentations.

In 1859, his cousin and successor the 7th Duke submitted the Folio to the scrutiny of Sir Frederic Madden, Keeper of Manuscripts at the British Museum, and Nicholas Hamilton, of that department, who pronounced that the emendations were incontestably forgeries of modern date.

Ingleby in collected form in 1859, with a full-page dedication naming Andrew Edmund Brae as the first to protest against the specious readings of the Perkins Folio, and, by the use of philological methods, the first to prove that they were modern fabrications.

Brae, now in his own name, reviewed the matter more at length in 1860,[26] and Ingleby gave a fuller account of the discussion raised by Collier's emendations in his Complete View of the Shakespeare Controversy (1861).

[27] During the later 18th century, literary forgeries had a certain esteem, when audacious impostures like the De Situ Britanniae, the pseudo-Ossian, the medieval poems of Thomas Chatterton, or the works of William Henry Ireland might carry their own worth, and capture the romantic imagination.

The case of Collier, in the mid-19th century, was different, because it was profoundly shocking to the scholarly establishment to discover that a long-established colleague in their midst, a person closely associated with the British Museum, the editor of numerous important editions, with privileged access to the primary documents of English literature, should become suspected of the systematic falsification of evidence and possibly the mutilation of original materials, especially in relation to William Shakespeare.

Much as Sir Edward Dering's forgeries had corrupted the historical record in ways that were then not yet recognized,[28][29] such a presence placed a question-mark over the authenticity of the whole resource, and over the work of other scholars whom he might have misled.

An attempt to redeem Collier's reputation from the charge of forgery was made by Dewey Ganzel in his 1982 study Fortune and Men's Eyes.

[31] He argued that Collier's accusers, led by Frederic Madden, were motivated largely by envy and class bias, and that they were upper-class dilettantes determined to put down a lower-class but ferociously hard-working and talented striver.