Haha I actually semi-researched this question in High School.
It wasn't practical, but dual wielding swords, back then, was a style some european and asian swordsmen used. Vikings did it as well. Whether or not western European knights did it during feudalism is a debate. There's accounts of who killed who, but imagine the movie Braveheart, once all hell breaks loose, who knows who's doing what. So there arent really paintings of dude twirling swords like Dayne.
In total war combat I imagine people would do whatever they had to do, use rocks, pick up double swords, do whatever. But back then medieval european knights were traditionally trained with a sword/lance/spear/axe/mace and a shield of varying sizes depending what type of knight/infantry man they were and the shield in itself could be used as a weapon, so it'd be uncommon for someone to go in with two swords alone. Knights wore all that chainmail to protect themselves, I doubt most would give up a giant piece of wood/metal that would add to that protection.
But i guess, that's why it's all the more bad *** when someone did.
But there's evidence of samurais, vikings, renaissance era swordsmen, gladiators, etc. dual wielding weapons.