As the spring auction season kicks off, $655 million in paintings and sculpture is up for grabs at Christie’s and Sotheby’s this week. The International Fine Art Fair, which opens to the public tomorrow, offers another $500 million worth of art for sale at the Park Avenue Armory. But a small gallery walk taking place just off the gilded sliver of Madison Avenue between 66th and 69th streets offers its own princely pleasures. Though practically all the work on view is also for sale, it can be enjoyed by art lovers for free beginning today.

Only six galleries strong and heavily weighted toward Renaissance paintings up through the 19th century, “Masterworks of Six Centuries” opened with an invitation-only vernissage last night. The featured exhibits will all be on view to the public through June 15.

“Last year, when we skipped holding the walk, we got a number of calls all asking, ‘When is the event?'” the gallery director of Didier Aaron Inc., Alan Salz, who first organized the gallery round-robin six years ago, said. This year’s walk features dealers Richard L. Feigen & Co., Dickinson, David Tunick Inc., Lawrence Steigrad Fine Arts, and Zwirner & Wirth.

The stature of some participating dealers is impressive. Mr. Feigen has made more than 100 sales to museums such as the J. Paul Getty Museum, the National Gallery of Art, and the Metropolitan Museum of Art. His current show, “Sublime Convergence: Gothic to the Abstract,” pairs Italian paintings and sculptures dating between 1230 and 1407 with work by postwar Americans including Brice Marden, Agnes Martin, and Mark Rothko — all of whom have work that will be auctioned at Christie’s next week. A Bernardo Daddi “Saint Domenic” (c. 1338), whose subject is draped in a black cape, hangs next to a 1968 Rothko painting drenched in depressive tones of black. A Barnett Newman painting, from the personal collection of architect I.M. Pei, is juxtaposed with a work by the artist known as Master of the Strauss Madonna, c. 1410. “The show highlights the enduring constancy of the spiritual in art,” Mr. Feigen said. In the background, piped-in Gregorian chants evoke a whiff of mysticism.

Particularly poignant is a polychrome carved figure of Joseph of Arimathaea (c. 1230), which has lost its lower arms and feet over time. From the Tivoli, Italy, Descent from the Cross workshop, the figure is a modestly priced $675,000 and would complement any top tier modern and contemporary collection.

At Dickinson, the exhibit “Power & Wisdom: Portraits in a Changing Europe” goes beyond the usual conventional portraits of British aristocrats. Henri-Pierre Danloux’s “Portrait of A’Kao” (1793), for example, depicts a Chinese émigré to London. Paris couturier Hubert de Givenchy, who dressed Audrey Hepburn, is a previous owner of the painting, which is now priced at $22 million. Amid the paintings are medieval, Renaissance, Baroque, and early 19th-century European sculpture on offer from London dealer Daniel Katz.

On 67th Street, Didier Aaron Inc. is showcasing “Francois-Joseph Belanger: Projects for Ceilings,” featuring watercolor, gouache, and pen and pencil work by the French Neo-Classical architect. Most enticing are the unfinished examples, which have a surrealist air. Priced between $5,000 and $30,000, these, too, are a relative bargain.

The recent success of Lawrence Steigrad, who just doubled his quarters by moving into a townhouse at 23 East 69 Street, signals the rise of Old Masters. “With more international fairs on my calendar, my business has more than tripled in the past five years,” Mr. Steigrad said. He is the only dealer in the country emphasizing 17th-century portraiture. Dutch and Flemish pieces are available for $75,000 and under.

Photography and contemporary art buffs should head to Zwirner & Wirth, a powerhouse with three London galleries, one in Zurich, and a fifth in Chelsea. Photographs by Robert Mapplethorpe, Bruce Naumann, and Sigmar Polke, as well as the ubiquitous Andy Warhol, are represented in its current show. “It’s only our second year in the walk,” the gallery’s manager, Greg Lulay, said. “The event draws an entire new audience to our gallery.”