it's impossible to be sure even about some aspects of early C20 performance styles, let alone those of earlier periods.

As far as as certain medieval performance practice goes it would be akin to giving four guys who'd never heard Led Zeppelin the song book & the instruments and expecting them to come up with Four. Although, that's what Rolf Harris did with Stairway to Heaven, refusing to listen to the original so he could approach it unbiased with respect of how it ought to sound - or so goes the legend.

With respect of the Medieval Baebes however (to get back on thread) one feels it's more about the hype than the music although I dare say in this day & age the two are indistinguishable. Personally, I'm happiest with those musicians who manifest an evident mastery (that can only be authentic) without feeling the need to accessorise - although in terms of a certain appropriate aestheticism I'm as gullible as anyone else.

Jordi Savall / Hesperion XXI - Canarios Improv