I don’t know about fingerless, but in the middle ages, regular gloves looked like this:

They’re occasionally called ‘shooting gloves’, but actually that is simply the level of articulation regular gloves were at back then. Here’s some more examples:

And here’s some reproductions from historical fiber artists:

“Three-fingered gloves hand sewn in wool. As seen in 14th century manuscripts such as the Luttrell Psalter.” [x]

[x]

“Nothing compares to the spocklike feeling you get from a three-finger mitten.” [x]

Here’s a pattern if you want to make some for yourself. There’s probably a lot more, check google or, if you want, look up your local SCA chapter’s textile or Arts and Sciences people and ask them if anybody has made some.

So, there you go! Medieval gloves/mittens! Live long and prosper!