Last year, the Royal Shakespeare Company festival of “The Complete Works” gave the venerable troupe the kind of boost it had lacked for well over a decade.

Yet many of those productions weren’t from the RSC .Some were brought in from other companies, and the quality was seriously mixed. In reality, it was an ambitious (and successful) publicity stunt.

However, true artistic vision and sustained intellectual and dramatic excitement were waiting in the wings. The RSC’s triumphant Histories Cycle, which began April 1 and runs through May 25, is not only a defining moment in the company’s history, it’s also a thrilling reminder of what the RSC can do better than any other company.

In a time when most artistic directors balk at the resources required to stage one Shakespeare play, the RSC’s Michael Boyd threw caution to the wind and gathered a creative team to stage eight at once.

Over 2½ years, they rehearsed and played “Richard II,” “Henry IV, Part I” and “Part II,” “Henry V,” “Henry VI, Part I,” “Part II” and “Part III” through to “Richard III,” the monumental cycle of 100 years of increasingly bloody history.

Played without intervals, this would be 24 hours of nonstop drama. That’s longer, and gorier, than a season of “The Sopranos.” And with its constantly recurring characters and themes of power, family loyalty, betrayal and revenge in narrative-driven chunks, it is not far-fetched to regard this as high-end Elizabethan soap.

In case anyone thinks it’s just more thematic programming, consider the statistics. The plays have 264 roles, played by an ensemble of 34 actors, each appearing in seven of the eight plays.

The result is magnificently theatrical. Verse-speaking at the RSC is not always everything it could be — actors often understand what they’re saying, but fail to energize a line’s dramatic purpose. But these actors have had Shakespeare’s verse, grammar and imagery in their minds, bodies and mouths every day and night for two and a half years. Out go “speeches” and in come pungent, idiomatic line readings borne out of natural delivery. Rarely has Shakespeare felt so completely communicative with its audience.

The other enormous boon is the animation of what is, essentially, ever-increasing backstory. Boyd’s casting means that recurring characters and those that repeat crimes and misdemeanors in successive generations are played by the same actors. This makes the patterns of behavior in the wars over kingship uncommonly legible.

It also allows auds to follow journeys across the plays. So-called “mad” Margaret famously has a tirade in “Richard III.” As designer Tom Piper observes, “Margaret’s cycle of curses, and Richard’s hatred of her, have a greater resonance when you have seen her stab his father, York, in the back in an earlier play.”

Piper’s arresting visuals are responsible for much of the productions’ success. In his suggestive vision, dogged literalism is banished in favor of powerful abstraction. In the company’s Stratford home and again at London’s Roundhouse, the action is placed on a large thrust stage dominated by a curved three-story tower against a similarly tall, rusted back wall.

That tower suggested the Tower of London, in which traitors — and kings — were incarcerated and executed. Yet it also serves as a raised playing area, an aerie from which characters could spy, a royal balcony or a besieged town wall.

Piper’s costumes — 800 of them — also evoke the period without the dead hand of authenticity. Richard II is crowned in full medieval-style garb, but many of the other costumes mix period shapes with hints of Elizabethan style and a battle-dress close to a World War I uniform.

Anyone imagining the RSC to be devoted to staid, interpretation-free reverence would be startled by Boyd’s dynamic use of space. Piper’s set allowed for multiple entrances from every angle, including soldiers roaring up through the trapped floor and, best of all, characters swarming down ladders from the auditorium’s wrap-around balconies and, in battle scenes, cascading down from the rig on ropes.

Entire battles take place with airborne actors swinging across the auditorium in genuinely daredevil feats of physicality.

It is fair to point out that, on a play-by-play basis, most of the productions have been equaled and sometimes bettered by previous productions, some, like Steven Pimlott’s incandescent “Richard II” in 2000, even at the RSC. But this overall achievement is on a wholly different scale.

Attending marathon performances — this critic saw all eight plays in a pair of 2-day stretches — what comes across in an astonishingly visceral sense is the intelligence of the productions’ throughline.

The season is likely to make stars out of Jonathan Slinger — a tremulous Richard II, marvelously bombastic Fluellen and a psychotic Richard III — and the beautifully terrifying Katy Stephens, whose incendiary Joan of Arc in “Henry VI” is matched by her icily controlling Margaret. Yet the notion of leading actors fades beneath the power of the overall conception, in which all characters are perfectly played within the narrative’s grand design.

Spurred on by the almost outlandish success of the project, Boyd is building another 2½-year ensemble company within the RSC to begin in 2009. The plays remain under wraps. But regardless of his choices, the season now has a formidable benchmark to measure up against.