How did the French defeat at Saint-Quentin in 1557 affect Catherine de’ Medici’s views of Spain?

The French defeat at the Battle of Saint-Quentin in 1557 was a pivotal moment in the life of Catherine de’ Medici. While her performance as regent during this crisis earned her widespread acclaim for her ability and eloquence, the military disaster served as the likely origin of her perpetual fear of Spain.1

This deep-seated apprehension regarding Spanish power became a fundamental "touchstone" for her political judgments throughout her career. Understanding this fear is essential to discerning the coherence of her later policies, which often involved navigating the complex, often adversarial, relationship between the French crown and the Spanish Habsburgs.12