OK so spin-off of a spin-off thread here…
Thinking about lingyi’s thread, and not wanting hijack it, it occurs to me that the big change in the manner of warfare in the modern era wasn’t between “civilized” pre-modern warfare, where armies of combatants would politely walk to a prearranged battles to fight each other, versus “uncivilized” modern “total war” warfare.
Warfare always had a “civilized” portion, where armies of combatants would fight pitched battles, and “uncivilized” portion where combatants would perform hideous acts against civilians, either while raiding, besieging, or fighting an “asymmetric” war against insurgents.
What actually changed IMO in modern warfare was (due to the size and technological sophistication of armies) confrontations between field armies moved from a single pitched battle at a specific location, to a wider front, where armies faced each other across entire regions simultaneously. World war one was the famous example of this transition. Are there any earlier examples?
The later Napoleonic battles got very large, but still had well defined, local, battlefields. The American Civil War featured sequences of battles in quick succession, but I don’t think the series of battles could really be described as a “front”. And there are plenty of historical examples of raiders and marauders ranging across long distances, but I am talking about the main body of the opposing armies.
Maybe the Franco Prussian war?