Portrait of Prince FF Yusupov Count Sumarokov-Elston. 1903 Valentin Serov (1865-1911)

The picture has something of this: cavalry, mammal, people, horse, seated, two, equestrian, woman, race, three, equine, livestock, stable, recreation, group, bridle, saddle.
Perhaps it’s a painting of a man riding on the back of a white horse next to a woman in a white dress and a.