Operational art obstacle

What prevented operational art from developing before the 1800 was the inability of most forms of information to move much faster that the troops themselves. Travellers and deserters made their way more or less at the same speed as armies did, rarely exceeding 25 miles per day. This meant that any enemy information they could provide would only arrive a fairly short time before that enemy himself came into view. So when Napoleon was asked how one fights a battle, he answered: “First you engage, then you see”, thus summing up all previous military practices.

Source: J. Olsen, M. van Creveld. “Evolution of Operational Art”.