William Holman Hunt. "The Finding of the Saviour in the Temple," 1854-1860. (COURTESY Birmingham Museums and Art Gallery)

In 1984, the Tate Gallery in London opened what was then the most important exhibition ever devoted to the Pre-Raphaelites — a group of English painters who sought to reform art by setting the clock back, stylistically, to the 15th century.

At the time Margaret Thatcher was battling coal miners in England, Ronald Reagan was declaring Morning in America, political conservatism was resurgent and nostalgia and nationalism were both in good standing. The moment must have seemed perfect, ready-made to revisit painters who, in hindsight, seemed devoted to old-fashioned ideas of naturalism, beauty and heart-on-the-sleeve emotion.

Now another Pre-Raphaelite show, also organized by the Tate, is opening at the National Gallery of Art, and what a difference almost three decades have made. When this exhibition debuted in London last September, it was called “Pre-Raphaelites: Victorian Avant Garde.” The brotherhood of artists who came together in the mid-19th century to oppose the brown, gloppy fustiness of history painting and Royal Academy of Art conservatism, were positioned as radicals, as an avant-garde movement advocating both political and artistic reform. Their characteristic backward glance to the age before Raphael was put in its proper historical context: as a cry against the disordered and often brutal world of industrialization and its attendant woes of poverty, cheapness and drab, despoiled landscapes.

The Washington version of the show is smaller, and it has lost the provocation of the original subtitle, although wall text refers passingly to “Britain’s first avant garde movement.”

“Pre-Raphaelites: Victorian Art and Design” acknowledges the painters of the Pre-Raphaelite Brotherhood — Dante Gabriel Rossetti, William Holman Hunt and John Everett Millais foremost among them — as innovative and concerned with social issues, but it doesn’t strenuously argue the “avant garde” claim.

William Holman Hunt. "The Lady of Shalott," 1888-1905. (COURTESY Wadsworth Atheneum, Hartford, Connecticut)

Perhaps that’s because it’s a hard claim to sustain, at least if you have in mind the history of modern art as it played out in France, where stylistic innovations are easier to detect and apparently more radical. The painters of the Pre-Raphaelite movement ended up as establishment figures — Millais eventually became president of the Royal Academy — and despite a handful of truly provocative works in their respective portfolios, they all aged out of the avant-garde label fairly quickly. When we think of avant-garde, we think of painters who aimed at radically rethinking not just how to make a painting, but how to see the world, and we don’t tend to think of the dewy-eyed gingers in medieval costumes painted by the Pre-Raphaelites.

So the change in emphasis may be completely reasonable. The Pre-Raphaelites are extremely problematic artists. Although they willingly allied themselves under an adopted name and declared themselves committed to similar aims — going forward by looking back — they are diverse artists and not easily categorized.

Some of them pursued a finicky realism to astonishing, almost photographic lengths; others stressed narrative and a fantasy of pre-industrial wholesomeness. Political ideals would lead some of them, especially William Morris, to a genuine commitment to socialism, while for others, the poor were best seen as decorative and deferential.

By the last room of the exhibition, where the love of detail has brought Hunt to the very edge of an almost dissonant abstraction and sensuous eroticism has morphed in the hands of Edward Burne-Jones into soft porn, it’s clear that any effort to define and contain the Pre-Raphaelites as a coherent group is almost impossible.

But it’s sad to lose the more vigorous claim that these artists were indeed avant-garde because only by arguing with that idea can you sort the radical from the retrograde in what they were doing.

The National Gallery presentation, especially the robust red wall colors, emphasizes beauty and radiance, and a temporary gift shop near the exit displays the group’s contribution to design (if you can afford a few hundred dollars for a roll of wallpaper, there are some lovely options). But it takes considerable work on the visitor’s part to get deeper into why these paintings were indeed shocking when new, and what was gained and lost when 20th century artists turned definitively away from the narratives and realism typical of the Pre-Raphaelites.

What often bothers us most today — the brilliant, even lurid colors of the early brotherhood paintings — also bothered viewers in the 1850s. Like the impressionists of a later generation, the Pre-Raphaelites got out into the sun and discovered there a blinding spectrum of color.

Almost every painting in the first room of the exhibition feels light-drenched, which has both a practical and metaphorical effect. The sun reveals detail, and its rising suggests rebirth, and the first room of the exhibition underscores how self-consciously English these artists were in their sunny sense of cultural renewal.

Three works by Ford Madox Brown take the English language as their subject: In one Chaucer reads to King Edward III, in another John Wycliffe reads from his first translation of the Bible into English, and a third, “The Seeds and Fruits of English Poetry,” places Shakespeare, Milton, Spenser and other literary luminaries against the archaic gold background typically used in the representation of saints.

There’s something thrilling in the youth and vigor on display, not just in the physically perfect human forms in a painting such as William Holman Hunt’s “Valentine Rescuing Sylvia from Proteus,” but in the young painter’s virtuoso rendering of grass and colored cloth reflected in the mirror-like surface of Valentine’s polished leg armor. Rossetti’s now iconic Annunciation from 1849-50, in which a red-haired Mary shrinks from a red-haired angel with a gesture full of fear, foresight and humility, is in many ways more beautiful than the ancient paintings it mimics, and it remains the most powerful attempt at re-imagining Christianity in the entire exhibition.

The reaction to some of these early paintings was fierce. A contemporary newspaper critic called the Rossetti “a provokingly clever monstrosity,” and while it’s hard to feel that way today, there are plenty of works nearby that more than merit the criticism. The brotherhood’s storybook Christianity was easily sentimentalized into tears and treacle, health and wholesomeness gave way to pious moralizing about fallen women, and the painters’ control over color loosened to the point of surreal garishness. Worse, however, is the sense that the artists retreated into a fantasy of life rather than a confrontation with it. Death loses its sting, and suffering people tend to suffer in luxury and comfort.

An early work by Millais, the 1850-51 “Mariana,” shows a character originally from Shakespeare’s “Measure for Measure” standing in front of a stained-glass window, through which a refulgently splendid garden is visible. But Millais can’t stop there, and the light gives way to darkness at the right side of the painting, where a small oil lamp is burning. It’s brilliant, but also a bit too provokingly clever, as if Mariana has deliberately requested stained glass windows to necessitate candlelight at midday. Her suffering — she has been exiled by her scheming beloved — isn’t believable. One imagines her drawling, “how much longer must I wear this spectacular dress and sit in this tediously beautiful room?”

Despite the initial shock of their work, the Pre-Raphaelites were beloved by men such as a Thomas Plint, a deeply religious and wealthy stockbroker, and Thomas Fairbairn a Manchester-based industrialist who was an enthusiastic and brutal union buster. To be both filthy rich and deeply Christian requires some editing to the basic Christian message, a focus more on the pleasing vignettes of Christ than his revolutionary message. William Holman Hunt’s “The Finding of the Saviour in the Temple” depicts a red-haired Christ as a barely pubescent boy in a richly colored purple smock, surrounded by the old men of the temple. But the most powerful message of the painting is its richness of detail, an Orientalist fantasy of gold walls, colored glass and intricately carved screens. Perhaps that’s Christ in the picture. But it might just as well be called “Beautiful English Boy in an Expensive Room.”

The Victorian world is far from our own, and its particular vain of smugness and hypocrisy is too easily lampooned in hindsight. We forget figures such as Alfred Tennyson, the Pre-Raphaelites favorite poet, and we stand on the far side of the great photographic divide from these painters who worked simultaneously with the development and spread of the machine-made image. Dickens thought the kneeling Mary in a famous painting by Millais was “so horrible in her ugliness,” but today it’s hard to feel the class prejudice that blinded him to her beauty.

In some ways, it seems the Pre-Raphaelite artists may have felt their own self-contradictory chaos as much as we do today. A recurring preoccupation for several of these painters was the Lady of Shalott, immortalized in a poem by Tennyson. The lady lived under a curse, confined to a room, weaving alone and viewing the world only through a mirror until one day Sir Lancelot rode by and she can’t resist his charms (“She left the web, she left the loom, she made three paces thro’ the room. . .”) And for looking at him directly, she is fated to die in a very picturesque way, floating down a river in a gentle bark while wearing a billowing white dress.

There are volumes to write about the poem’s depiction of female sexuality and transgression, but it also stands for what may have been a deep anxiety among the painters. Were they in fact confronting the world directly, or through the artifice of mirrors and art? Hunt’s late, great painting, “The Lady of Shalott,” is presented as the last work in this exhibition. She is depicted at the poem’s climax, when after her fatal act of looking at the world, the mirror cracks and her weaving flies apart into a tangle of threads. It is a stunning work, and it reaches a level of visual complexity — decorated walls, the world seen through a mirror, a frenzy of auburn hair, flowing fabrics, glinting silver — that takes representational painting to the point the late romantic composers took music just before Arnold Schoenberg cleaned the Augean stables of tonality.

Everything falls apart, cracks, dissolves. It leaves one wondering if Hunt knew at some level, akin to our own guilty pleasure in looking at these works, that they were never entirely honest, the world was never really confronted openly, that artifice always had the upper hand. One wonders if he was as baffled by what he and his fellows had achieved as we are still, today.

Pre-Raphaelites: Victorian Art and Design is on view at the National Gallery of Art through May 19.