Memory is one person’s distortion of the past. History is that of the consensus. The latter may be more reliable and factual, but the former can be more illuminating and cinematic. It can also be, within its subjective limitations, closer to the truth, especially when transformed by a genius such as Federico Fellini in his 1972 masterpiece, “Roma,’’ recently re-released on DVD by the Criterion Collection.

A single documentary can’t contain an entire city with its multiplicity in time and place and its multitudes of souls, but it can express the documentarian’s experience of it. In silent classics such as Walter Ruttman’s rhapsodic day-in-the-life of a metropolis, “Berlin: Symphony of a Great City’’ (1927), and Dziga Vertov’s dizzying four-city tour, “Man With a Movie Camera’’ (1929 ), as well as Guy Maddin’s more recent, oddball masterpiece, “My Winnipeg’’ (2007), documentaries have long employed imaginative means to convey a reality that is more psychological than materialistic.

Psychology for Fellini meant Carl Gustav Jung, whose more mystical alternative to Freudian analysis began to influence the director in the early 1960s. It inspired the near solipsistic self-exploration of his masterpiece “8½’’ (1963) and the surreal and sentimental “memoir’’ “Amarcord’’ (1973). Fellini ventured with this Jungian point of view into the distant past in “Fellini Satyricon’’ a grotesque adaptation of Petronius’s satire of ancient Roman decadence, and into the world of today with the seemingly structureless series of vignettes in “Roma.’’

The vignettes represent the gradual progression of the filmmaker’s consciousness from the fringes of the city, both geographical and psychic, to its ineffable heart.

It begins with the authorial voice-over (delivered not by the squeaky-voiced Fellini himself but by mellifluous voice actor Adalberto Maria Merli) describing his first encounter with Rome — an ancient milestone outside his hometown of Rimini, shot at dusk with the silhouettes of peasants — one bearing a scythe, like Death — migrating to the big city.

Fellini learns more about Rome as a schoolboy from his Fascist-era teachers. A pedantic headmaster takes Fellini and his fellow uniformed students to the banks of the Rubicon — now a puny trickle — to reenact Caesar’s fateful crossing and his famous quote “Alea iacta est!’’ (“the die is cast!’’).

In a school assembly monitored by priests, slides are shown of various classical artifacts, including an image of the she-wolf that suckled the city’s mythic founders Romulus and Remus. Then the scene disintegrates into laughter and threats of damnation from the scandalized clerics because some trickster has snuck in an image of a woman’s posterior.

Finally, on the eve of World War II, the callow, good-natured 18-year-old Fellini (Peter Gonzales) enters the city himself. It is 1939, and his first exposure includes a rooming house and al fresco banquet of urban gluttony, crudeness, high spirits, and picturesque squalor that is like a lower class, Fascist-era version of “Satyricon.’’

As someone comments later about the raucous crudities of a vaudeville music hall, “It is a modern day Saturnalia. A combination of the Circus Maximus and a brothel.’’ This link between eras is underscored in a haunting image of a nocturnal street fitfully illuminated by a welder’s torch. The shadows of whining stray dogs cast on the wall resemble the sculpture of the mythical she-wolf from the schoolroom slide show.

“But what of Rome today?’’ asks the laconic narrator. Like the scene in “La Dolce Vita’’ (1960) in which a baroque statue of Christ is hoisted by a modern-day helicopter over the ruins of a Roman aqueduct, Fellini portrays the present as interlayered and contemporaneous with the past.

Approaching the city along the newly constructed autostrada with his documentary crew riding on a camera crane, Fellini records a traffic jam in a downpour. The scene includes, along with honking vehicles and squashed cattle from an overturned truck, such phantasmagoria as a riderless white steed and a peddler with a cart.

Later, the documentarians accompany the supervisor of a project excavating a new Roman subway. Drilling halts when it encounters a chamber containing a perfectly preserved Roman home, with frescos staring from the walls. But once the wall is pierced the air rushes in and the frescoes fade into nothing.

That these “documentary’’ events are mostly shot on Cinecittà soundstages does not, for Fellini, diminish their veracity. Instead, since the world is what is perceived by the imagination through the lens of the collective unconscious, the artificiality of these scenes enhances their reality.

There is no question that one of the film’s most entertaining and ultimately frightening sequences is an elaborate artifice. In the decaying palazzo of a moribund princess, an audience of nuns, priests, and church hierarchy assembles to enjoy an “ecclesiastic fashion show.’’

Backed by Nino Rota’s score (it sounds like a diabolical variation on “Dance of the Sugar Plum Fairy’’), clerics in increasingly bizarre vestments strut, roller skate, and bicycle along the catwalk, with robes and mitres adorned with mirrors and flashing lights. The silliness gives way to uneasiness, as the costuming becomes macabre, with glittering empty vestments spangled with skulls, skeletons, and cobwebs. Finally the audience falls to its knees in awe and adoration as the show unfurls its piece de resistance: an enormous, radiant monstrance of many subtle colors, pulsating with hallucinogenic malevolence, enshrining a creepy facsimile of the face of Pope Pius XII.

Fellini ends his movie not with an embrace of his beloved city, but a flight from it, or at least from this dead, apotheosize patriarch at its heart. Scores of motorcycles zoom through the empty night streets, zipping past the history of Rome as enshrined in its ruins, down to the autostrada, and like latter-day vandals, into the world beyond.

“Roma’’ is available from the Criterion Collection on DVD ($29.95) and Blu-Ray ($39.95). For more information go to www.criterion.com/films/28039-roma.

Peter Keough can be reached at petervkeough@gmail.com.