What is the meaning or origin of the idiom "a Shakespeare and a Scott"?

I came across this idiom, "a Shakespeare and a Scott," which I have found in several different writings, and haven't been able to ascertain its origin, meaning, or an appropriate synonym.

"Poetically classic ground does not, alas! occur with us, as on the shores consecrated by a Shakespeare and a Scott." - Sir Samuel Ferguson in the Ireland of His Day, p. 100.

"How extraordinary that a great and powerful empire like Great Britain, uniting as she does every facility and requisite for its cultivation and development, should be so insensible to its value—a country which has produced a Bacon, a Newton, a Milton, a Shakespeare, and a Scott—a country which has excelled in every other walk of human genius and enterprise!" - Remarks on Ancient and Modern Art, pp. 394-395

"The reason why they omit it is that it is impossible for any but a Shakespeare and a Scott to touch it with any kind of life, spirit, delicacy, and truth." - The Token and Atlantic Souvenir, p. 274

Shakespeare is obviously a reference to the playwright, and it appears Scott refers to Walter Scott, a renowned English novelist.

My guess is it is a way of emphasizing the difficulty of a task, capable of being successfully completed only by one with profound intellect and skill, and as for a generic synonym, perhaps genius? Is anyone familiar with this idiom and its origin?

Here is a quick review of the three instances of “a Shakespeare and a Scott” cited in the posted question:

Mary Fergusson, Sir Samuel Ferguson in the Ireland of His Day was published in 1896, but the instance of “A Shakespeare and a Scott” that it contains appears in the form of an extract from an article by Samuel Fergusson titled “Attractions of Ireland—No. II: Scenery and Society” from Dublin University Magazine, published in September 1836.

The essay “Painting,” by “An Amateur” appears as the final essay in Remarks on Ancient and Modern Art, in a Series of Short Essays, which was was published in 1837.

“The Modern Job; or, The Philosopher’s Stone” appears, without a byline, in The Token and Atlantic Souvenir: A Christmas and New Year’s Present, published in 1834.

So the three examples that the poster cites appeared within four years of each other, in the middle 1830s.

Searches of the Google Books and Hathi Trust databases turn up, in addition to those three instances, eight others, ranging in date from 1838 to 1871. Here they are, in chronological order.

From an 1838 [review of The Drama’s Levee], cited in Revue: A Story in Pictures (1971[?]) [combined snippets]:

Of The Drama’s Levee; or, a Peep at the Past, (16 April 1838) a contemporary critic says:

'We have already said that The Drama's Levee is the best of the Easter novelties, but we have yet to add that it is decidedly the best piece of the kind that was ever brought out. It abounds with wit without absurdity, satire without ill-nature, and smart touches at the existing abuses of the drama without one spark of injustice. Added to this, the splendor in which it has been got up equals any former effort of the sort at this theatre, and the expense incurred must have been enormous. The title of the piece unfolds its nature. The Drama (most admirably played by Mrs. Orger) being awakened from a lengthened slumber, summons the representatives of the different theatres to inform her of what is going on in the theatrical world. These are accompanied by Praise and Censure, (Madame Vestris) and Mr. Bland,) whose remarks are full of point and double entendre; the legitimate and illegitimate sons of the drama also attend; the first dressed in a Roman habit and the second in a dress half harlequin’s and half that of a Spanish grandee. They, however, begin to squabble the moment they appear, and ultimately the natural son un-naturally drives his brother from the place. Specimens of the recent productions of the different theatres are now presented, not omitting the Gnome Fly, which recently buzzed in the public ear at the Adelphi. This gives occasion for some admirable sarcasms on the part of Censure, which was one of the best played parts in the piece ; but nowhere is the lash inflicted more stingingly than on the desecration of the Surrey—that spot over which the acting of an Elliston, and the united genius of a Shakespeare and a Scott had flung a blaze—by the introduction of Jim Crow.

From George Young, On Colonial Literature, Science and Education: Written with a View to Improving the Literary, Educational, and Public Institutions of British North America (Halifax, Nova Scotia: 1842):

Are not these causes sufficient to account for the difference between ancient and modern eloquence, and to vindicate the theory I have endeavoured to reason out, that if Demosthenes or Cicero had lived in this age, their fame as thrilling and impassioned orators would not have been so brilliant and transcendant? Be it remarked, however, with becoming humility, that upon this subject, we can only speculate. It is a pure question of metaphysics, which we are unable to reduce to certainty. Nature may have created only one Demosthenes—one Cicero—one Newton—a Shakespeare and a Scott; upon these she may have conferred the higher attributes of divinity—there is a curtain beyond which we cannot pierce, and before it we must bow,—for, with all our knowledge, we know little of the lamp which burns within.

From “Incomprehensible Nature of the Love of Christ” (August 1, 1847), reprinted in Memorials of the Late Hugh Mair, D.D. (Sermons, Addresses, &c.) (Toronto, Ontario: 1879):

We may have all the wealth of a world at our disposal ; we may have all the authority and dominion which a crown and a sceptre can confer ; and have all the powers of intellect which ever distinguished a Shakespeare and a Scott in the world of romance, and the philosophy of human nature ; a Milton and a Pollock in the regions of poetry ; a Locke, a Stewart, and a Brown in the philosophy of mind ; and an Edwards, a Dwight, and a Chalmers in the more elevated department of a sublime theology ; in short, we may have all the giant attainments of the greatest of men ; but, if we have not within us a well-spring of kindly, generous and lofty evangelical feeling, we must turn out a curse to ourselves and to all who are within the spheres of our withering, desolating, ruining, damning influence.

From Robert Dabney, “On Dangerous Reading,” in the [Richmond, Virginia] Watchman and Observer (1849), reprinted in Discussions, volume 2 (1891):

It is the attribute of a favored few, whose knowledge of men and things springs from a sound philosophy, has been cultivated by large and varied experience of life, and is guided by a powerful understanding. How vain to expect this rare historic wisdom , only attained in part by one or two in the lapse of centuries—such as a Shakespeare and a Scott—in the pert , shallow, dreaming babblers whose frothy inventions deluge the country!

From A Lady, Rural Rambles, Or, Some Chapters on Flowers, Birds, and Insects (Philadelphia, Pennsylvania: 1854):

Useful and pleasing as the study of Nature unquestionably is, it ws for a long time greatly neglected. Yet there have been in all ages minds of the highest order, which have directed all their energies to this most rational pursuit. A Shakespeare and a Scott have not bestowed more pains in delineating every shade of character among men, and in pursuing every river and streamlet of passion , as it boils and meanders in the human breast , than a Linnæus and a Smith in observing the qualities of inferior objects, over which man is the appointed lord: nor have poets of eminence disdained to exercise their genius in describing vegetables and insects.

From Peter Davidson, “The Infidel Opinion,” in Opinions Concerning Jesus Christ (Edinburgh, Scotland: 1857/1858):

The authors of these writings [the gospels] have not told us that he was such and such a person, having such and such a character. They deal very little in this kind of description. They have told us, on the other hand, what he did and what he said, leaving us to gather for ourselves what kind of person he was ; and this is a mode of writing, be it remembered, which, while easy and natural in the case of truth, is the most difficult of all modes in the case of fiction. It is in this species of writing that the loftiest triumphs of human genius, like those of a Shakespeare and a Scott, have been achieved.

From “Wisdom and Courtesy,” in Henrietta Keddie, Heroines in Obscurity: Second Series of ‘Papers for Thoughtful Girls’ (London: 1871):

A large amount of sympathy with one’s neighbours’ interests is the nearest faculty—or condensation of faculties—to the highest order of genius. Shakespeare and Scott were wonderfully endowed with this world-wide sympathy. ... The guest whom a Shakespeare and a Scott would not have found unworthy of their respectful consideration, is turned over [by shallow girls] with characteristic shortsightedness and selfishness, as a subject just fit for the over-strained energies of tolerant fathers and patient mothers or aunts.

From “The Theatrical Experiences of the Late Alexandre Dumas,” in Dublin University Magazine (March 1871):

Of all writers, living or dead, Alexandre Dumas stood highest in his own estimation. The noble, unselfish, and heroic traits of character, which he imputes to himself in his Mémoires, would not be unworthy of a personage in whom the finest qualities of a Homer, a Shakespeare, and a Scott were combined. We have omitted the greater part of this self glorification, retaining merely those relations, in the lives of Parisian men of letters towards the theatre and the public, which are any way interesting, and of which Dumas' own career furnished so many curious examples.

Walter Scott died in 1832, two years before the earliest writer cited in this answer used the precise form “a Shakespeare and a Scott” to yoke him to Shakespeare as exemplary eminences in English literature. Such was the admiration for Scott’s novels in the 1830s that the phrase seems to have enjoyed at least some slight currency as a stock evocation of, in effect, “the greatest of all English writers in drama and the novel.” Notably the phrase appears in works published across much of the Western English-speaking world, from England (three), Ireland (two), and Scotland (one) to the United States (three) and Canada (two).

But literary tastes changed and Scott’s books didn’t, and the decline in critical estimation of his oeuvre is evident in the dwindling number of original published appearances of “a Shakespeare and a Scott” reported by Google Books and Hathi Trust: 1830s, four occurrences; 1840s, three; 1850s, two; 1860s, zero; 1870s, two; all subsequent decades, zero.

Today, if you told someone that you aspired to the sublime heights of “a Shakespeare and a Scott,” your listener might very well answer, “Who—Robert Burns?” As far as I have been able to determine, no writer since 1871 has used the wording “a Shakespeare and a Scott” to indicate a sincere pairing of Will and Sir Walter as equally luminous immortals.