One of the more remarkable Old Master pictures to surface at Sotheby’s New York this past January was a previously unknown Portrait of Pope Benedict XIV by Pierre Subleyras (1699-1749). Signed and dated 1746, the modestly sized canvas has been owned by two French collectors since the mid-19th and early 20th century and was in remarkably fresh original condition, uncleaned and unlined. Modestly estimated at $100,000-$150,000, the portrait sold to New York dealer Adam Williams for a record $986,500, and is on its way to the Metropolitan Museum of Art.

Like his great predecessor Nicholas Poussin, Subleyras made his career in Rome, where he settled shortly after he won the Prix de Rome for The Brazen Serpent (1726, Musée des Beaux-Arts, Nîmes). His fame was solidified by his enormous, 22-foot-long Christ in the House of Simon, (1737, Louvre) painted for the Refectory of the Order of Saint-Jean de Latran, which to the chagrin of his Italian colleagues made Subleyras the most sought-after painter in Rome.

Though he gained his reputation as a painter of grand religious compositions, Subleyras was esteemed for his incisive and subtle portraits. The artists’ protector in Rome, the powerful Cardinal Valenti Gonzaga, introduced him to the Papal court, and shortly after the coronation of Benedict XIV (the former Cardinal Prosper Lambertini) in 1740, the new Pope asked Subleyras and Agostino Masucci to compete in producing his holiness’ official likeness -- the highest honor bestowed on any painter. Masucci’s portrait, now in the Accademia di San Luca, Rome, was rejected (it was likened by Anthony Clark, the great scholar of 18th-century painting, to a "chilled hippopotamus”) and Subleyras received the coveted commission.

Restrained by the specific state requirements for the commission, Subleyras produced an official Papal portrait, now in the Musée Conde in Chantilly, that is a disappointingly uninspired work, a rather generic three-quarter-length composition of the fleshy, vapid-faced pontiff, enthroned before a table littered with documents, his hand raised in blessing. Judging from this portrait (and especially by the increasingly dull copies made by the artist and his studio), it is hard to see exactly why Subleyras was such a sought-after portraitist.

Paraphrasing playwright Christopher Durang, the Metropolitan Museum’s new Subleyras portrait of Pope Benedict XIV explains it all for you. The blank, smooth formality of the earlier work is replaced by a portrait of uncommon sensitivity and candor, painted five years after the official portrait. As before, the pope is clad in his official scarlet robe and ermine-tripped cap, but here he confronts the spectator face-on, the intense gaze of his pale blue eyes reflecting intelligence and kindness, his plump lips beginning to curve a wry smile. The balloon-smooth surface of the pontiff’s face in the Chantilly portrait is replaced by a keen observation and almost tactile rendering of the softly varying surfaces of the sitter’s pale flesh. A likely private commission between sitter and painter, it is perhaps the most human and beautiful portrait by the artist, and one of the most remarkable Papal portraits since Velasquez’ Pope Innocent X.

The appeal of the picture is magnified by our knowledge of the sitter, who was perhaps the most sophisticated, beloved and popular pontiff until John XXIII. Though liturgically conservative and uneven in his treatment of Jews (he thought it was his duty to pursue by all means their conversion, yet he personally intervened to stop a violent pogrom in Poland, energetically defending the Jews and enjoining the Polish archbishop and primate to protect them), he was otherwise uncommonly open-minded, seeking a greater rapport between the Catholic Church and Protestants, Eastern Orthodox Christians and Muslims.

Possessing a warm personality and sharp wit, he was a reformer who curtailed luxuries and abuses within the church, and strongly promoted scientific studies and the collection and translation of ancient manuscripts. In his private life, he surrounded himself with scholars, artists and writers of all kinds. "I have been reproached," he once said, "because of my familiarity with Tasso, Dante and Ariosto, but they are a necessity to me in order to give energy to my thought and life to my style.” Respected and admired by Catholic and Protestant alike throughout Europe, Benedict even earned the admiration of the anti-clerical Voltaire, with whom he enjoyed a lively and friendly correspondence. The caustic philosopher warmly described him as "the pride of Rome, the father of the world, who teaches that world by his writings and honors by his virtues.”

The Portrait of Pope Benedict XIV is not the first painting by Subleyas to enter the Met’s collection. As the artist died early at age 50 (reputedly from overwork), his pictures are rather uncommon, and most of them are in museums and churches in Italy and France. They are rarer still in American public collections, the finest being two small oil sketches of Seven Angels Adoring the Christ Child and The Emperor Heraclius Carrying the Cross recently acquired by the Los Angeles County Museum of Art and two delectable secular canvases depicting scenes from two of La Fontaine’s fables, Brother Luce, the Hermit, with the Widow and her Daughter and Brother Philippe's Geese in the Museum of Fine Arts, Boston.

While the Metropolitan’s collection of French 18th-century paintings is rich in the sensuous, playful Rococo of Watteau, Nattier, Boucher, Greuze and Fragonard, it had long felt the absence of a major Subleyras. A superb start was made by the 2007 purchase of The Mass of St. Basil, a modello, or oil sketch, for a mosaic altarpiece in Santa Maria degli Angeli in Rome. Though several variations of this modello exist (including in the Louvre and the Hermitage), the Metropolitan’s canvas (still in its original frame and the only one signed and dated) is by far the finest. Retained by the artist, it can be seen (complete with its frame) in Subleyras’ painting of his studio interior, a work now in the Akademie, Vienna.

The existence of the other versions may have tempered enthusiasm for the Met’s picture when it surfaced at a sale at Piasa in Paris on Dec. 13, 2006, where it sold to New York dealer Jack Kilgore for a bargain-level €220,000. The Met purchased it (for a price quoted as "in the high six figures” or "very low seven”) a few weeks later.

That a Subleyras of comparable importance if of very different character should surface two years later is a remarkable occurrence, and it is to the Met’s credit to have purchased a second masterpiece (for a similar price) by the artist so soon after the last. With the acquisition of Subleyras’ Portrait of Benedict XIV, both specialties, portraiture and history painting, of a remarkable and rarely encountered master are magnificently displayed.

PAUL JEROMACK is a New York critic and journalist.