Duct tape

Duct tape, while not being used or even known during period, is a very handy item... and they would have used it if they'd had it!

Uses include:

• holding armor together
• holding garb together
• holding tents together
• holding just about anything together (but don't expect duct tape to help in (most) relationships.)

"Duct tape is like the Force. It has a light side and a dark side, and it holds the universe together."

Ok, so this isn't medieval, but hey, it's a good use for duct tape!