A recently rediscovered painting by Velázquez sold for just over $3 million at Sotheby’s in London in an auction that saw several record-breaking sales for fellow Old Masters. The long-lost portrait of the most powerful woman in 17th-century Rome was a highlight of the July 3 auction, which totaled an impressive $70.7 million.

Velázquez’s portrait of Olimpia Maidalchini Pamphilj (1591–1657) shows the so-called “Mistress of the Vatican,” who exerted a powerful influence on her brother-in-law (and reputed lover), Pope Innocent X. She earned the nickname “Papessa” (the lady pope). Some see her as a proto-feminist.

The portrait, which was once in the collection of Don Gaspar Mendez de Haro y Guzmán, was lost for close to 300 years until it appeared, unattributed, in an auction in the 1980s. When the painting was brought into Sotheby’s Amsterdam office recently, it was described as “anonymous Dutch school.” Mysterious markings on the back led researchers to discover the true identity of the artist.

The auction house’s head of Old Master paintings, James Macdonald, said in a statement that the rediscovery represents “a highly significant addition to the great Spanish master’s oeuvre,” adding that the painting can be counted “among only a handful of works” by Velázquez that remain in private hands. It was painted by the Spanish artist during his “golden period” when he visited Rome in 1650.

The rediscovered work sold for £2.5 million, neatly within its estimate of £2 million to £3 million. (All final prices include the buyer’s premium). The evening sale brought in a total of £56.2 million ($70.7 million), the third highest for an Old Master sale in London.

The sale also saw a new auction record for a work by Thomas Gainsborough. The British artist’s 18th-century landscape, Going to Market, Early Morning, sold for £8 million ($10 million).

The Metropolitan Museum of Art acquired Johann Liss’s The Temptation of Saint Mary Magdalene at the auction. Courtesy of Sotheby’s.

New York’s Metropolitan Museum of Art went shopping at the sale, acquiring Johan Liss’s The Temptation of Saint Mary Magdalene for £5.7 million ($7.1 million). The canvas fetched five times more than the artist’s previous auction record, which was established in 1994 for the same painting. Sotheby’s Old Masters co-chair Alex Bell noted after the sale that the sensuous work had “caused a sensation during the pre-sale exhibition.”

A work on paper by Jean-Étienne Liotard sold for $3 million, and new auction records were set for works by Giannicola di Paolo, Sebastiano del Piombo, Altobello Melone, Peeter Baltens, Jusepe de Ribera, and Andrea Sacchi.