Why did knights wear heavy armor?

Answer: Protection from swords and arrows

Heavy armor scared enemies away — Wrong. Armor wasn't meant to scare enemies—medieval soldiers expected to face armored opponents. Knights wore armor for direct protection from lethal weapons. Looking intimidating was not the point; surviving combat was.

Protection from swords and arrows ✓ — Correct! Medieval warfare involved swords, lances, arrows, maces, and axes. Plate armor (developed over time) provided excellent protection—distributing impact force and stopping cuts. A knight in full armor was difficult to kill in melee combat. Weight (40-55 lbs) was manageable when distributed across the body. Protection, not status or tradition, was primary.

Tradition required full armor — Wrong. Armor evolved over centuries from mail to plate based on effectiveness against weapons, not tradition. Knights wore armor because it dramatically increased survival in battle against swords, arrows, and other weapons. Effective protection drove adoption.