Strategic Planning Changed Overnight

Firearms upset the balance between offense and defense. More mobile versions of the cannon that had proven their worth in France in the mid-1400s entered Italy with a bang in 1494 [C.E.]. Charles VIII of France swept down the length of the peninsula to Naples in a matter of weeks with an army of 18,000 and a horse-drawn siege train of 40 or more cannon. Fortresses that were expected to resist for months were taken in a matter of days. Strategic planning changed overnight. Everything now depended on stopping the enemy in battle before he reached the walls of the city.

— Firearms: A Global History to 1700, p. 62