LONDON—The Christie’s King Street salesroom overflowed on July 7 as the house rolled out its first-ever auction combining Old Masters and 19th-century art. The session beat its estimate of £15 million ($24.1 million), realizing £20,284,400 ($32.8 million). Of the 63 lots offered, 48 found buyers, for a sell-through rate of 91 percent by value and 76 percent by lot.

Although the two-hour sale included big names in 19th-century art, such as Jean-Auguste-Dominique Ingres and J.M.W. Turner, 51 of the 63 lots were Old Masters. The 10 highest prices went to paintings done before 1900, several of which shattered expectations. Among these were a still life by Willem Claesz Heda, which a telephone bidder picked up for £1,385,250 ($2.3 million) — nearly triple its high estimate of £500,000 ($812,000) and a new high for the 17th-century Dutch artist — and a portrait of a young man by the 16th-century Florentine painter Giuliano Bugiardini, which leapfrogged its estimate of £150,000 to £250,000 ($244-406,000) to make £825,250 ($1.4 million), also an artist’s record.

The race to the top ended in a tie, with works by Fra Bartolommeo and Michele Giovanni Marieschi both bringing £2,169,250 ($3.5 million). Marieschi’s view of the courtyard of the Doge’s Palace, the sale’s cover lot, went to the New York dealer Otto Naumann, while an anonymous U.S. private buyer snagged the Bartolommeo, a 1516 portrayal of the Madonna and Child with St. Elizabeth and an infant St. John the Baptist that had once been part of the renowned Cook Collection, at the Doughty House, in Richmond. Paintings by the Florentine master rarely appear at auction, and although the hammer price was a touch shy of the work’s low estimate, it was still a record.

Despite such triumphs, the Christie’s sale was a mere prelude to the bravura performance of the two Old Masters auctions at Sotheby’s on July 8, which between them contained about twice as many lots. Kicking off the day was a single-owner sale of 56 Renaissance and Baroque masterworks from the collection of the Johnson & Johnson heiress Barbara Piasecka Johnson, who was a major collector in the 1970s and ’80s. The session’s highlight — and the most-talked-about painting of the week — was Jusepe de Ribera’s Prometheus (est. £800,000-1.2 million; $1.3-2 million), an emotionally charged canvas, with a strong appeal to modern taste, depicting the tortured Titan having his liver devoured by an eagle. The painting last sold 20 years ago, at London’s Matthiesen Gallery, for around $300,000, according to Guy Stair Sainty, a London dealer in European paintings, who describes Ribera as "a 17th-century Francis Bacon." Seven bidders competed for the work, which sold — to great applause — to a European buyer in the room for £3,849,250 ($6.3 million), an auction record for the artist. "Strong, direct images are well received by today’s market," says Alexander Bell, co-chairman, with George Gordon, of Sotheby’s Old Master paintings worldwide.

The Johnson session realized just under £10 million ($15.9 million) against an estimate of £5.2 million to £7 million ($8.4-11.4 million) and achieved impressive sell-through rates of 94.6 percent by value and 78.6 percent by lot. Almost all the action, however, took place over the phones, as those in the salesroom talked loudly among themselves, much to the dismay of auctioneer Henry Wyndham. The audience seemed to be anxiously awaiting the various-owners sale, which began an hour and a half later and grossed £26,134,050 ($42.4 million). Of the 48 works in that session, 33 found buyers, for a sell-through rate of 81.6 percent by value and 68.8 percent by lot.

Three phone bidders competed for Anthony Van Dyck’s half-length Portrait of Endymion Porter, driving its price above its high end of £1.5 million ($2.4 million) to £2,057,250 ($3.3 million). And Gabriel Metsu’s A Woman Selling Game from a Stall sold to the London dealer Johnny Van Haeften for £1,161,250 ($1.9 million), falling short of its low estimate of £1.2 million ($2 million) but establishing an auction record for the 17th-century Dutch artist nonetheless. The house nearly set a record for Pieter Brueghel the Younger when the artist’s Massacre of the Innocents (est. £2.5-3.5 million; $4-5.7 million) fetched £4,633,250 ($7.5 million).