If the historical identification is correct the sitter was the wife of Gaspard III de Coligny, Maréchal de Châtillon (1584-1646) who became Marshal of France in 1622, though a Protestant. The costume suggests a date of c. 1625-30, the standing lace collar, slashed sleeves, soft bodice, curled hair; all may be compared with Honthorst of the Buckingham family 1628 (RCIN 406553); this would make the sitter about 30 years old, by which time she had had four children. The canvas has clearly been extended to the sides and would originally have measured approximately 190 x 130. 

This portrait may be identified with the work listed as sold from Hampton Court in the Commonwealth Sale (p. 194, no 147), ‘Ferdinand Elle, Madam de Schaillion, sold to Bass 19/12/51 for £21’. the style is certainly consistent with an artist from the circle of Ferdinand Elle (1570-1637).

Inscribed lower left Madm la Mareschalle de Chastillon