Gustav II Adolf of Sweden at Battle of Breitenfeld in 1631, painting by Jean Jacques Walter, Thirty Years’ War, Germany, 17th century This painting of Gustavus at Breitenfeld is notable for its background depiction of his innovative deployment of forces—in two lines, one reinforcing the other, supported by his mobile field artillery. (NPL – DEA Picture Library (Bridgeman Images)) NPL – DEA Picture Library (Bridgeman Images)