The man who refused both
An argument with two sides usually ends when one side wins. This one ended differently, when a third man arrived and threw out both. Around mid-century Gustave Courbet looked at the reason wing’s idealized antique gods and the feeling wing’s heightened storms and decided he wanted neither. He would paint only the plain, contemporary, unidealized present, and he would paint it big. Two laborers breaking rock by a road, a whole provincial village turned out for a funeral, peasants and stone and ordinary dirt, given the grand scale David had kept for Roman heroes and Delacroix had filled with catastrophe. No ideal past. No sublime terror. Just the ordinary now, painted as if it mattered as much as a god.
This was Realism, and it is the hinge into the next era. By rejecting both the idealized past of Neoclassicism and the raised pulse of Romanticism, Courbet opened the long modern argument about what a painting is even for, the argument the Modern era carries from here. The line-versus-color fight that Ingres and Delacroix waged did not die with them either; it went on organizing French painting for another fifty years, straight into the academic establishment that the Impressionists would later have to fight.
The question it handed on
So between roughly 1750 and 1850, European painting argued out, in pictures, a question the whole modern age would inherit: is the truest art the one that orders the world by reason, or the one that tells the truth of feeling? Neoclassicism answered with line, the antique, and civic virtue, and became the face of a Revolution. Romanticism answered with color, nature, and the sublime, and painted the era’s terrors and longings. The two never took turns; they overlapped and fought, both of them riding the same flood of revolution and war. And when Realism finally walked away from both to paint only the plain present, the swing long buried and the oath long sworn, the modern age had begun.