Wine has been around for thousands of years - long before the technology to manufacture stemware. My impression from ancient and medieval artwork is that wine used to be consumed from cups or horns (speaking of which, in medieval Europe, did the host provide the cups, or were the guests expected to bring their own, as with cutlery?) When did it become customary to start drinking wine from glass stemware? And at what point did it become customary to have different shapes of stemware for different kinds of wine?
Stemware existed in antiquity. Those are glasses recovered from a shipwreck in the Mediterranean during the Principate. Here's another example, I think from Roman Egypt. And the famous Lycurgus Cup, in which there are particles of gold suspended in the glass, so that its color changes when light is behind it. That's just glass stuff, too. When you ask about stemware are you only asking about glass stuff? Because we've got stuff like this going way back into the early Iron Age. Do Attic κύλικες count? Footed drinking vessels with stems are not especially uncommon in antiquity. Are we talking about glass stemware, or just fancy shmancy stemmed drinking vessels used for wine in general (in which case the κύλικες are a perfect example, pretty much only wine was drunk from a κύλιξ)? I'm afraid I can't really answer your question in full because I don't know much about "wine culture," so to speak, but if we're talking about actual drinking vessels and their shapes that's another story
