STOP. Don't haphazardly combine things from 500 to 1500 into a single setting or story or image. It's been done, and it isn't pretty. We have a tendency to compress time periods that are farther away from us, rolling them all together. We would never dream of mixing the 40s and the 70s because those decades are so distinct to us. Because of their distance, the 1100s and the 1300s might appear to be interchangeable in terms of philosophies, modes of dress, architecture, you name it. But they aren't. If you're going to start combining things from various periods, at least be aware of what you're doing.
Here's a good place to start. That's the wikipedia category for medieval costume, where you can look at a period (usually lumped into a hundred-year group, so we still have to do some telescoping) and get a feel for its clothing. You'll notice that the changes are actually rather marked. A tunic is not a tunic is not a tunic, as it were. There is detail there to explore and mashing together different periods without really being aware of what you're doing sacrifices that detail for no real reason (and makes those people who know the difference cringe curiously).
For that matter, stop depicting shields of any type as being solid metal plates. At best they were covered in a thin layer of metal but were 90% simply wood with leather over them and a metal boss and rim. No one ever used a solid metal shield. No one. Don't do it. The only reason to depict a shield that way is ignorance and now you can't even lay claim to that defense anymore because I just told you.
And if you're thinking that because you're doing fantasy it doesn't matter, maybe you shouldn't be doing fantasy anymore. Or else stick to pulp stuff. Because honestly, how serious can you be if you don't care?