NEW YORK — Back in January, the muralists arrived, tiptoeing into the Pierre Hotel in Manhattan at midnight. They erected scaffolding in the grand oval space known as the Rotunda Room, climbed up and stretched out on their backs, daubing at the painted clouds that have long drifted across the sky-blue ceiling.

Then, in June, they turned to the shiny faux-marbling on the stair railing (so dated), applying a subtler matte finish. And last month, under the direction of architect and decorator Daniel Romualdez, electricians installed theatrical lighting to highlight the room’s signature feature, its fantastical wall mural; floor contractors polished the parquet; and new furniture arrived.

These efforts — the results of which were recently unveiled — have resurrected one of New York’s most spectacular gathering spaces. Beloved by brides who have taken their vows in the fairy-tale setting and familiar to members of the city’s upper crust who have mingled here during charity events, the Rotunda Room had languished.

But as new boutique hotels unveil hip hangouts, the 86-year-old Pierre is capitalizing on one of its own common areas — and not just for the benefit of those travelers who check into its guest rooms and of occupants of its full-time residences, but anyone who wants to revel in the Rotunda Room’s romantic atmosphere.

In fact, the room has been reinvented repeatedly since the hotel opened in 1930.

Designed in Georgian style by architects Schultze & Weaver, the Pierre joined a cluster of luxury hotels around the southeast corner of Central Park. Rising 44 stories on Fifth Avenue and East 61st Street, it combined lavish leased residences with hotel rooms, offering guests the thrill of possibly sharing an elevator with Elizabeth Taylor, Yves Saint-Laurent or any of the other luminaries who have called the Pierre home.

What made the buff-colored brick tower stand out — in addition to its copper mansard roof floating above the treetops of Central Park — were its social spaces. The main ballroom had marble columns and mirrored walls. The dining room — overseen by Auguste Escoffier in the early years — was walnut-paneled with gold curtains.

To reach those spaces one passed through the Rotunda Room, originally called the Oval Foyer. With its decorative plaster ceiling, stone walls and marble stairs, it looked like a room from a French castle.

But not for long. Within three years of the hotel’s opening — and with the country plunged into the Depression — the extravagant décor was deemed excessive and was simplified.

It was 1967 — after the Pierre had become a co-op, with residents purchasing their apartments and hiring the first in a series of hospitality companies managing operations — when the artist Edward Melcarth painted the Rotunda Room’s mural: a Renaissance loggia peopled with mythological characters and, seemingly, whomever else he fancied throwing in. Jacqueline Kennedy climbs a staircase. The actor Erik Estrada appears as Adam, eying a gamine Eve in slacks and a boho top.

Some members of the gentry, including Kennedy, weren’t happy about appearing in the mural and requested that they be removed, according to recently found hotel records. The Pierre responded by painting over telltale facial details, giving the visages a more generic look (though the former First Lady is still instantly recognizable).

“It’s over-the-top, even a little bit camp,” said Romualdez, who first encountered the extravaganza in the 1980s.

But by the early 2000s when Romualdez returned to the Pierre to renovate fashion designer Tory Burch’s apartment, the Rotunda Room was less lively. After a formal afternoon tea was eliminated, the furniture looked rather forlorn.

Until Francois-Olivier Luiggi, the general manager of the Pierre, which is run by Taj Hotels Resorts and Palaces, decided to revive the space.

The carpet is yet to arrive, but the menu is set: Weekdays a center table is piled with meringues, macarons and lemon-blueberry cake. After 7 p.m., light supper fare is served. Thus, visitors can sustain themselves while trying to guess the identity of the man in the mural wearing the blue Nehru jacket — or the guests across the room.