Fighting an open field battle with only melee weapons, like Braveheart

Hundreds of infantry on both sides colliding in a wide open flat field. What weapon do you go with? Sword and shield? A polearm? Two swords?

I'm thinking light weight and nothing that will leave me open to attack should I miss. A two handed weapon, like a fauchard, would be great for keeping a distance but lots of torque to leave me open if I miss a swing.

You would also have to be quick since there would always be the threat of someone coming from behind and shanking you while dealing with another threat. I'm thinking bladed cestus, which would make my hands look similar to the comic character Wolverine's.

Quick in and out, little additional torque on my swings, low weight for mobility and fast turns.