How did gunpowder artillery weaken medieval castles?

Gunpowder artillery fundamentally altered siege warfare by rendering the high, vertical stone walls of medieval castles vulnerable to direct bombardment. In the 15th century, the development of effective cast-bronze siege cannon allowed attackers to breach these previously formidable curtain walls with unprecedented speed and force.1

While medieval fortifications were designed to withstand traditional threats like battering rams or mining, they were ill-equipped for the kinetic energy of heavy cannon fire. High walls, which had once provided a defensive advantage, became liabilities because they offered a large, stable target for artillery battery. This vulnerability was demonstrated dramatically in 1453 when Mehmed II used large bombards to breach the walls of Constantinople, and again in 1494 when French artillery breached the fortress of Monte San Giovanni in just eight hours.1

In response, military engineers abandoned high, vertical masonry in favor of lower, thicker profiles and earthen ramparts, which were far more resistant to cannon shot. This evolution eventually led to the development of the bastioned trace, a sophisticated system of projections designed to eliminate dead space and provide defensive fields of fire.123