In the Renaissance, the art of warfare became one of the main fields of application of mathematical sciences. The advent of firearms stimulated the development of a new science, ballistics, which consisted in the geometrical analysis of the relationship between the angle of the gun, the weight of the projectile, and the range. Some instruments, such as the bombardier's square, plumb rules, proportional compasses, and calipers, were standard kit for gunners. Other instruments, such as the radio latino, the a rchimetro, and the altazimuth square, were used instead to measure distances, the profiles of ramparts, and the layout of fortresses. Special goniometers were devised to prepare plans for fortresses with curved profiles that would avert or deflect the impact of projectiles.