For a long time, the identity of the woman in this portrait was a mystery. But lengthy investigations have revealed that she is probably Annie Oud-Dinaux (1893-1990). Charley Toorop worked with Annie’s husband J.J.P. Oud on an exhibition at the Stedelijk Museum in Amsterdam in 1928. Oud, an architect, was associated with the De Stijl movement, and Annie Oud-Dinaux preserved his archive and legacy after his death. Partly thanks to her hard work and efforts, De Stijl is known around the world today.