The sitter has not been identified. Both the style and the costume (particularly the collar) suggest a date in the second half of the 1640s. At that time Bol's portraiture still displayed the strong influence of Rembrandt's work. The pentimenti (alterations made by the artist to areas already painted) in the fan suggest that the artist adjusted the composition slightly during the execution of the painting.
The National Gallery, Trafalgar Square, London WC2N 5DN