I came across this citation in the OED entry1 for fag (4th meaning, "a knot in cloth"):
1464 Act. 4 Edw. IV, c. i, ― En cas que ascune autiel diversite ou Rawe, Skawe, cokell ou fagge, aveigne destre en ascun part des ditz draps.
I think that refers to an act of law as opposed to a play but, either way, what language is that? Presumably some variant of English but which? It seems far closer to French than modern English. What I understand of it, I glean from French and Spanish. My English doesn't help at all.
So, what is this English (?) called? Based on the year, I assume it must come under the general heading of Middle English, but I can make far less sense of it that I can of, for example, the Canterbury Tales. Is this a different language? Not Middle English at all?
1 Available here, if you have access.