How did bastioned fortifications defend against attacking soldiers and artillery?

Bastioned fortifications were designed to counter the destructive power of cannon and the threat of infantry assaults by replacing high, vulnerable medieval walls with low, earth-backed structures.1

Defensive Mechanisms

• Eliminating Dead Space: The bastion—a projection with two faces and two flanks—allowed defenders to provide flanking fire along the curtain walls and the faces of adjacent bastions. This eliminated the "dead space" at the base of walls where attackers could otherwise hide.12
• Sunken Profile: Walls were lowered into the ground behind a ditch and shielded by a glacis, a sloping earthen rampart that protected the main wall from direct artillery fire.3
• Firepower: The polygonal shape of the bastions provided uninterrupted fields of fire and allowed for larger defensive batteries to be mounted along the parapet.2
• Outworks: To further protect the main walls, engineers added outworks like ravelins and demilunes to force besieging batteries further back and delay the attacker's progress.2