Jacob Vrel, Known Only by His Name, and His Painting “Woman at a Window”

All that is known of the author of this painting is his name, inscribed on several dozen other works created between 1654 and 1662, presumably in Delft and Haarlem. Jacobus Vrel is one of the most enigmatic of the Little Dutch Masters, and mystery hangs over his canvases too, "Woman at a Window" among them. Whom is she looking at? Is it a child or a ghost? Why is it pressed so close to the glass? What emotion is that face meant to show? And, above all, what is this infant or spirit doing there at so late an hour?