One day in 1995, a few years after joining the Design Department of the Metropolitan Museum, Daniel Kershaw was standing in a stairwell off the Tapestry Hall when he noticed a strange protrusion in the wall.

“It was a slight circular bulge, with the beginning of a crack,” Kershaw said the other day. At the time of the discovery, Kershaw and some colleagues were restoring the stairwell’s cast-iron railing, following an 1874 drawing by the museum’s first architect, Calvert Vaux, and his collaborator Jacob Wrey Mould. After consulting the few surviving Vaux and Mould drawings, Kershaw speculated that something interesting might be hidden behind the bulge—namely, an oculus.

An oculus (the Latin word for “eye”) is a round opening, often at the top of a dome but sometimes set into a wall or a landing. Vaux’s building, a barnlike red brick structure in the High Victorian Gothic style, which today forms the center-most section of the museum, had included an oculus on the middle landing of each of four stairwells. There was no doubt that one pair of oculi had been destroyed, but Kershaw had hopes for the other two: “I would tell people, ‘One day, I’m going to get in there.’ ” Earlier this year, when the museum renovated the Tapestry Hall, he did. In March, Kershaw and a team of workmen chopped through thick layers of plaster with small chipping drills, revealing the outlines of the oculi. The openings had been filled in with brick, and a few electrical wires ran through them. The team carefully removed each brick by hand.

Last week, a new gallery devoted to the art of the High Middle Ages opened in the renovated space behind the Grand Staircase. High up on one wall, seventy feet apart, were two round openings, each six feet in diameter. Standing in the space a few weeks earlier, Kershaw had pulled out some of Vaux’s old plans for the building from the eighteen-seventies. It was almost unrecognizable: a center hall was separated from the side vestibules only by columns, and the interior was encrusted with Victorian ornament. One drawing, showing an elaborate molding around each oculus, made Kershaw laugh. “It’s so fussy!” he said. “But this didn’t make it into the final design. Maybe someone talked Vaux out of it, or maybe he came to his senses.”

The architectural history of the Met spans more than one century, twelve firms, five master plans, and seventeen wings, but if there is a dominant theme it is this: bringing Calvert Vaux to his senses. Vaux had won the commission based on his standing as one of the masterminds of Central Park, but his initial museum building was declared, by its irascible president, “a mistake.”

“Vaux was off the job almost as soon as it opened,” Morrison Heckscher, the museum’s resident expert on its architectural past, said. Vaux’s master plan was too ambitious and costly, and Victorian design was slipping out of fashion. By the end of the century, new architects had begun executing a plan to completely surround Vaux’s exterior with other structures; by the nineteen-fifties, the interior decorations had been stripped. “Basically, they came up with brilliant ways to make a building disappear,” Heckscher said.

Initially, at least, Vaux’s oculi were appreciated. In 1880, the Times reported, “The circular windows, which are at the intermediate landings, are so alluring, giving such pleasant glimpses of the rooms, that one must fain linger for a moment to look within, and an unconscious rest is gained.”

Heckscher said, “Vaux wanted transparency, a concept that is very appealing to us in the art world today.” He went on, “When you looked through the oculus, you looked out over a sea of glass cases. It was like going into Wanamaker’s or Macy’s. It was a way of showing off the goods.”

The bird’s-eye view of the new gallery will be similarly dramatic: the tapestries have been moved to another room, and a peek through one of the oculi from the stairwell now reveals a splendid crucifix and a burst of colorful stained glass. The oculi have been altered in one important detail: what were once open airways now hold panes of glass. These, Kershaw explained, were a necessary precaution. “We suspect that moderns might not be as well behaved as their historical counterparts.” ♦