This is a slice of a portrait by Gutsav Klimt of a picture called Judith I, which was painted in 1901. I saw the picture in a gallery in Vienna on a holiday there years ago, pre children, when my wife and I walked around the city enjoying everything to do with Art nouveau (or the secession movement).
Since seeing the Klimt at the Osterreichische Galerie Belvedere I think some of the Klimts they had have since be reclaimed as property that was taken by the Nazi's and has recently been auctioned by the rightful owners. The impact of seeing rooms with original Klimt paintings in was almost overpowering and something that, although only a slice, this bookmark reminds me of.
