Your Curated Tumblr Experience Awaits!
When in doubt, go to primary sources. This picture is a drawing of Irish soldiers by Albrecht Dürer, 1521. Gallowglass and Kern, the gallowglass are the two on the left wearing the padded gambeson and the maille shirt with the burgonet. Gallowglass were (originally)Scottish mercenaries from the highlands hired by Irish nobles as heavy infantry, though in later years they incorporated locals into the companies. See the dude on the left with the claymore? Carries it like a polearm over his shoulder. See the Kern on the right? Holding the claymore under his brat (mantle)? He's acting as a sword bearer for the gallowglass with the spear. He's got the blade wrapped up in his brat so it doesn't cut him.
Here's a landsknecht of the Renaissance, a German mercenary and a doppelsöldner (double pay man) by his weapons. The zweihander he's carrying is to break up the large blocks of pike by chopping through the pikes and then dismemberment of the lightly armored pikemen.
The whole greatsword scabbard discourse gets me because, like, we know the answer to this one. We've got primary sources talking about it. The answer to "how do you carry a weapon that's more than a yard or so long" is:
If you don't think you'll need it on short notice and you're lucky enough to have access to a wagon or other means of transport, you don't carry it at all – you stick it in the wagon.
If you do think you'll need it on short notice or you don't have a wagon, you just carry it in your hands everywhere you go and constantly complain about how dumb and awkward that is, unless you're a professional mercenary and/or independently wealthy, in which case you hire a guy to follow you around carrying it in his hands everywhere you go and he complains about how dumb and awkward that is (though probably not while you're listening).