Sotheby's New York will next month sell a rare terracotta relief of the Madonna and Child by Donatello. The work, which is estimated at $4m.-$6m., once belonged to one of the most important art patrons of the Lombard region in the Quattrocento. It has been known to scholars over the past few decades, but was hidden beneath as many as ten layers of stucco and paint that had been added over the last 500 years, obscuring not only its beauty, but also its attribution. Only recently has significant cleaning revealed its beauty. The relief will be offered in Sotheby's sale of Important Old Master Master Paintings and European Works of Art, to be held on January 26/27 in New York. The same sale will include a rediscovered Rembrandt, the small Elderly Woman in a White Bonnet, estimated at $3m./$4m., as well as many other exceptional works, including a stunning still life by Jan van Huysum ($6m./$8m.), a view of Venice by Bellotto ($3/$4m.), and a portrait of Napoleon's mother by Baron Gerard ($700,000/$1m.).