How did a bastion improve a fortress's defensive firepower?

A bastion improved a fortress's defensive firepower by projecting outward from the main wall, which allowed defenders to eliminate "dead space" directly below the parapet. By incorporating two flanks and two faces that terminated in a salient angle, the bastion enabled defenders to provide both direct and flanking fields of fire against attackers.12

This design was a critical evolution in fortification following the 15th-century realization that cannon fire could easily breach traditional medieval walls. By utilizing a "bastioned trace," engineers could protect the main walls from artillery bombardment while ensuring that no area at the base of the wall remained undefended from the musketeers and gunners positioned within the works. This system remained a dominant feature of military engineering for approximately 300 years.12