Why did Francis I’s cavalry charge fail at the Battle of Pavia?

At the Battle of Pavia, the cavalry charge led by Francis I failed primarily because it was an outdated, medieval-style tactic ill-suited for the emerging era of gunpowder warfare.1

The charge was ineffective for two main reasons:

• Obstruction of Artillery: By riding his armored cavalry in front of his own cannons, Francis made it impossible for his artillery to fire upon the imperial forces.1
• Vulnerability to Firearms: The French forces were decimated by Spanish arquebusiers, whose early firearms proved devastating against the traditional cavalry charge.1

Compounded by thick fog that caused battlefield confusion and a lack of support from his Swiss mercenary pikemen, the charge failed to break the imperial lines, ultimately leading to the annihilation of the French army and the capture of the king himself.1