At the New York Film Festival, a period piece promises something slightly more adventuresome than buttoned-up butlers and half-caught sighs. Exhibit A: Eric Rohmer’s “The Romance of Astrée and Céladon,” a flummoxing tale of estranged lovers in fifth-century France, where the presiding religion is Druidical. Glowing with edenic beauty and clad in pre-stitch cloth, the young couple, played by Andy Gillet and Stéphanie Crayencour, confuse each other into separation and pose Socratic conundrums about love’s image, in a story featuring a cross-dressing scheme and a jester-like gadfly out of Shakespeare.

As the first week of the festival opens tonight (with Wes Anderson’s “The Darjeeling Limited”), “Romance” is not the only feature to adopt the constraints and mores of earlier eras and explore the dramatic contours that result. Mr. Rohmer may be at one extreme, presenting, like Manoel de Oliveira, the 800-pound-gorilla answer to “What kind of film does an over-80 director make?” But the week’s other films find inspiration in disparate settings, from 1950s American suburbia to pre-breakup Communist bloc to a religious community that, though present-day, seems to set time out of joint.

The festival’s first must-see, the harrowing “4 Months, 3 Weeks and 2 Days,” opens with an innocuous, perplexing close-up of a fish tank, followed by some elliptical fussing-about at a Romanian dorm in the 1980s. What ensues for a college student and her devoted roommate is an unsentimental abortion drama that banishes any confusion in chronicling the helpless, grim sacrifices required in the face of the criminalization of the procedure in the then-Communist state.

Romanian director Cristian Mungiu follows pregnant Gabita (Laura Vasiliu) and friend Otilia (the uncannily alert and modulated Anamaria Marinca) onward to their rendezvous in a hotel with a warped underground doctor. Respectful and unflinchingly direct exactly when it’s called for, “4 Months” ultimately centers on Otilia and subtly closes a circle from her tough-minded but selfless acts of solidarity and friendship, to her gendered impasses with her boyfriend outside a dinner party.

Mr. Mungiu employs, with restraint, the long takes, central-act elongation, and ethical-emotional elaboration that seem to be his country’s unofficial house style, to judge from the recent Romanian wave headlined by “The Death of Mr. Lazarescu” (a 2005 festival selection). Surly hotel concierges, a queue of hopelessly bundled shoppers, flickering fluorescents, and prized black-market Kent cigarettes populate his snapshot, but they are quotidian details rather than mordant satirical fillips.

To judge from the Germanic language spoken by its sun-toughened farmers, Mexican filmmaker Carlos Reygadas’s “Stellet Licht” (“Silent Light”) appears to posit a little-known bygone prairie in the Low Countries, where wives wear old-fashioned frocks and bonnets. In (unexplained) fact, it’s a Mennonite community in Mexico that hosts the film’s barrel-chested father, Johan, his golden-haired family of seven, and his adulterous ardor for another woman.

The unblinkingly rendered beauty of the landscape (complete with lens flares) and of people’s lined faces seem to lay bracingly bare Johan’s dilemma and his wife’s suffering, which is somehow deafening in the high-plains silence. Mr. Reygadas’s use of nonprofessional (and slow-speaking) actors makes the laconic drama feel anguished with an almost off-putting directness, much like that of ’70s-era Werner Herzog hypnodrama. The title may sound like a lost Bergman film, but what “Stellet Licht” explicitly invokes is Carl Theodor Dreyer’s “Ordet,” with the spectacular power of belief and community of its final moments.

“Married Life,” directed by Ira Sachs, adopts not only setting but also genre from America circa 1949. Filling the overblown suburban adultery slot, this so-so adaptation of a John Bingham novel gets caught between ill-conceived melodrama and a crippling voiceover, with stranded performances to boot (Chris Cooper as the noble-hearted philanderer, Patricia Clarkson as his wife, and Pierce Brosnan as another leathery shark-in-best-friend’s-clothing). Barring a concluding dinner tableau of motivations that effortlessly suggests what might have been, “Married Life” is, as they say, routine.

For reinvigorating old paradigms, you’d do better to check out the festival’s special screening of a gender-troubled 1921 version of “Hamlet,” with Danish silent star Asta Nielsen playing the prince as a woman pretending to be a man. The biggest shape-shifting remains yet to come (in Todd Haynes’s Dylan pastiche “I’m Not There”), since the festival, per usual, hits on all cylinders in its second week, when our itinerary will include badlands unsuitable for the elderly, paranoid parks, strip clubs, and guided tours of Paris by red balloon. All aboard.