I'm reading a book by Ian Mortimer at the moment about the Middle Ages, and he put forth an interesting idea: That people (specifically in England at the time, he doesn't speak to other places) didn't have a real concept of the development/evolution of cultures in a great historical sense. The illustration he gives for this is the fact that the figures in church wall paintings and other art at the time were, regardless of their actual period of being, depicted in contemporary garments/styles of Middle Ages England.
On the surface this makes sense, but also seems like too sweeping a conjecture to me -- is it? What was the sense of historical cultural development (in anything from fashion to philosophy) like in the Middle Ages, among the various groups in society?
I've written about this before in the context of Benedict Anderson's (rather confused, in my view,) comments about the difference between medieval and modern notions of simultaneity, and in particular his suggestion that:
Figuring the Virgin Mary with ‘Semitic’ features or ‘first-century’ costumes in the restoring spirit of the modern museum was unimaginable because the mediaeval Christian mind had no conception of history as an endless chain of cause and effect or of radical separations between past and present. (Imagined Communities, 23)
I don't know exactly what comments that Mortimer makes on the subject, but it sounds like he is drawing on the same sort of history of mentalité that Anderson is finding in Bloch and Auerbach. In which case my comments at the end of the first post and the second should broadly address your concern here.
More broadly, see the post I link there by /u/ARHistChalAl: here. And you may also find relevant this post by /u/j-force on Gerald of Wales and medieval notions of Civilization. (I've also commented more briefly on the same material here with an eye towards notions of developmental stages of civilisation.)