With modern metallurgy and technology, could you make a suit of armor that would make a man nearly invincible by medieval standards?

Like, medieval steel must have been a bit shit.

Could you craft a sword out of titanium or carbon nanotubes that would slice through that era's steel like it was paper?

And likewise, could you craft a suit of plate armor that would shrug off whatever people of that area could throw at you using kevlar and plexiglass and advanced ceramics or whatever?

I guess I'm asking is how unstoppable could you make a man to swords and arrows and the like?