La caza de Atalanta y Meleagro Nicolas Poussin (1594-1665)

The picture has something of this: cavalry, people, seated, mammal, group, many, man, cowman, herder, veil, livestock, lid, sword, weapon, saddle.
Perhaps it’s a painting of a group of men riding on the backs of white horses in front of a crowd of men on either side of a white horse.