Doesn't look medieval to me. I'd guess early modern, somewhere in the 17th-19th century range, and likely a token.
It doesn't look medieval to me, looks more like a late 17th century token. Looks to me to be possably Dutch or French, somewhere around there.
On the obverse you can read: STADT. M - VNSTER. So it should be 1 Pfennig from the city of Münster (German state). No date visible but the design matches the 1600. Nice coin, I don't know about the value, but I'd have bought it for 3-4 USD.