There's a misunderstanding that the Middle Ages were really the Dark Ages, where people sat in mud huts, dug mud, were covered in dirt and crap, and some lived in Anarcho-Syndicalist communes and didn't know we had a king.
Really, the Middle ages weren't all
that bad. And they weren't a grand fall from grace, but a continuation of progress. We may have lost the arches, but Europe was doing things that had never been done before. And to them, it was the Modern Age. And it's not like a situation where while they were digging in the mud, someone discovered an ancient Roman text and all of a sudden they civilized again. They evolved and developed into the Renaissance in a natural progression. And then the Renaissance people disavowed the whole age previous, and acted like everything between them and the Romans was an age where people sat in mud huts, dug mud, were covered in dirt and crap, and some lived in Anarcho-Syndicalist communes and didn't know we had a king.
Also, a lot of people don't seem to pay attention to the fact that the Barbarians when they initially took over from Rome weren't digging in the mud either. They were reasonably developed for the era. Or at least that's what Terry Jones has taught me. Terry Jones also feels that the Renaissance is pompous and overrated. It's an interesting thought. If you'd like to see, he has a whole BBC series called "Barbarians" and "
Medieval Lives" you can find on youtube easily.
Anyway, you can't maintain some "Dark Age". But, you could perhaps maintain the way society operated, along Feudal lines and such.