The Arezzo Cycle – Battle between Heraclius and Chosroes (detail) Piero della Francesca (1415/17-1492)

The picture has something of this: people, group, cavalry, many, Renaissance, veil, man, book, kneeling, god, manuscript, baby, Gothic, sword.
Perhaps it’s an open book with a painting of a group of people and horses in front of a crowd of men and women, all of which are holding flags.