In 1558, Italian sculptor Baccio Bandinelli was in the midst of creating a monumental Neptune to tower over the Piazza della Signoria fountain in the center of Florence.

But Bandinelli died shortly after he was commissioned to sculpt the sea god, leaving behind a carefully crafted miniature model of his vision.

That piece, “Neptune,” will soon be on display as part of an exhibit of Renaissance statuettes at the National Gallery of Art.

“Bronze and Boxwood: Renaissance Masterpieces from the Robert H. Smith Collection” opens to the public on Sunday. More than a dozen works have been acquired and added

to the collection of bronze, boxwood and ivory statuettes since it was last on view at the National Gallery in 2002.

Senior Curator of Sculpture and Decorative Arts Nicholas Penny praised the breadth of the collection, which includes pieces by celebrated European sculptors Antico, Giovanni Bologna and Giovanni Francesco Susini.

“This collection has grown enormously,” Penny said. “It’s increased in number, but … perhaps the single most important sculpture in the collection has been acquired since its last exhibition here.”

The piece to which Penny was referring is one of the smallest among the works. At just 7.5 inches tall, “Seated Nymph,” a bronze statuette with mercury gilding on the drapery and hair and silver-foil eyes, is prominently displayed in a glass case in the center of one of the gallery rooms, allowing the viewer to examine the intricate details and rich, bronze finish of the sculpture from every angle.

“It’s a pity we can’t handle all the pieces, but you’ll have to do that in your imagination,” Penny said of the work’s dynamic texture and design.

[IMGCAP(1)]“Seated Nymph,” which was made for Marchesa of Mantua Isabella d’Este by Antico in 1503, embodies artistic trends of the early 16th century.

“At the time, they were extremely interested, especially in Northern Italy, in this Renaissance revival — the revival of the antique,” said Karen Serres, Robert H. Smith research curator.

Other noteworthy pieces include an early version of Bologna’s famous “Birdcatcher” and several “functional bronzes” — oil lamps, candlesticks and inkwells fashioned into ornate and often grotesque mythological beasts.

Though the works vary in medium, size and function, each piece shares intricate detailing and rendering of texture.

“I hope that the exhibition does actually make people think about the relationship between small sculpture in different medium,” Penny said.

The show gives heed to both the original craftsmanship of the pieces and the extensive conservation efforts undertaken by National Gallery staff.

Museum conservators, led by the Robert H. Smith Research Conservator Dylan Smith, employed a technique called x-radiology to reveal hidden imperfections in the seemingly flawless bronzes and identify casting techniques used to create and repair the pieces.

“I would say that one of the great things about my position here as a curator, as a senior curator in the National Gallery of Art, is that I’ve been able to work so very closely with the objects’ conservators,” said Penny, who is leaving his position to become the director of the National Gallery in London this week. “There can be no other institution in the world where the conservation and the curatorial departments have been so close and so profitably close.”

National Gallery Director Earl A. Powell III highlighted the significance of the collection.

“We are very fortunate to have an important collector such as [National Gallery President Emeritus] Robert Smith make … probably one of the most outstanding of these collections in the world of Renaissance sculpture available to the gallery visitors in the next several months,” Powell said.

The exhibit, “Bronze and Boxwood: Masterpieces from the Robert H. Smith Collection,” will run through May 4. The National Gallery of Art is located on the National Mall at Sixth Street and Constitution Avenue Northwest. It is open 10 a.m. to 5 p.m. Monday through Saturday and 11 a.m. to 6 p.m. Sunday.