This is especially the case regarding changes in the sword. ... The edges can still be used against more lightly-armored opponents: no matter how effective a sword is against forms of armor such as brigandine and mail, no sword, no matter how sharp, can cut directly through plate armor.

Are swords useless against armor?

>He puts it a bit too general, but against full plate armour, swords are nearly useless. they are useless for penetration. ... A spear or halberd were much more effective than swords. Swords were partially ceremonial and partially "nobility" weapons.

Can swords cut through modern armor?

Modern metals would make better and stronger swords than they had in medieval times, but it would make little difference in a fight. The sword would last longer before losing its edge, but it wouldn't be some kind of super weapon that could slice through plate armour or cut through blades.