Now I'm gonna answer my own question and say that heavily armoured men-at-arms used them. The fact that someone is willing to go into the battlefield without a shield signifies that you're either a noble or high ranking soldier so you're far enough from the chaos or your armor is good enough that a shield in unneeded.
Despite the popularity of the longsword, from what I've gathered, it wasn't as widespread as normal one-handed, maces and warhammers. It seems after the 13th century or so, the longsword was more of a status weapon or fencing weapon instead of a battlefield weapon.
What I would like to know would be the following:
- how practical it actually was
- why it was popular for so long
- which nation/people used it most
- what battles were its use was the most important or significant
Now, discuss!