Michelangelo set fires that destroyed thousands of his sketches to keep other artists from copying his work. One of the surviving creations, now worth an estimated $4 million, is an unfinished drawing "of a well-developed male, probably from a naked studio model," says William O'Reilly, director of drawings at Christie's auction house in New York.
The 16th century sketch, "Study of a male torso," is to be offered at a Tuesday auction -- one of several works by famed artists up for sale this week. Sotheby's auction house will be offering a rediscovered painting by Rembrandt and a sculpture by Donatello, both masterpieces that had been altered and painted over.
The Michelangelo, which belongs to an unnamed Swiss collector, is going on the block as part of Christie's sale of Old Master and 19th century drawings. As the greatest living artist of his time, Michelangelo was afraid others might copy his creations and had burned tens of thousands of them in his lifetime, O'Reilly said. "It was a kind of Renaissance copyright."
About 600 Michelangelo drawings survive, but fewer than five are in private hands worldwide.
Donatello's 15th century terra-cotta sculpture of a Madonna and child is a major work, said Margaret Schwartz, a European art expert at Sotheby's.
The "Borromeo Madonna" had been removed from a church outside Padua, Italy, in 1902 and was sold to a collector in Oregon, eventually ending up in Amsterdam, "covered with 10 layers of stucco and paint, in a drab-green color. And the child's groin area was covered with drapery," Schwartz said.
Rembrandt's "Portrait of an Elderly Woman in a White Bonnet" -- likely the artist's maid -- had been off art experts' radar screens for more than 70 years when it surfaced in a home in Fort Worth, said George Wachter, a Sotheby's Old Master expert.
The woman's collar, which the Dutch artist made a luminous white, had been painted over as a fur collar "to make her look richer -- and the painting more salable," Wachter said.
X-rays of the 1640 painting revealed the white collar under the fur -- applied later with paint that lab tests showed was relatively new. Other tests on the wood Rembrandt used to paint on showed that it had come from the same tree used for four other works created in his Amsterdam studio.
Both the Donatello, estimated at $4 million to $6 million, and the Rembrandt, estimated at $3 million to $4 million, are to be auctioned Thursday.