Indeed, although there is a bit of mythos surrounding the
   rediscovery. The BBC rendering of history still clings to old
   notions of dark/middle ages, even though that's discarded by
   historians now. The knowledge stayed intact elsewhere, but
   Europe _was_ in a crap state for a few hundred years. The
   beginnings of Scholasticism in the 11th century started to see a
   shift though. The start of the University system, with the
   assistance of the writings they had of aristotle and especially
   improved with 11th century commentaries. However, a HUGE boost
   came about during the Council of Florence in the mid 1400s. It
   completely failed in its aims to reunite the Eastern Churches
   and the Latin Church, who had gone her own way a few centuries
   before that, HOWEVER, the Byzantines, likely in a compassionate
   move, brought along a scholar named Gemistus Pletho along with
   others scholars, to help re-introduce the classics of Byzantine
   thought to an intellectually needy West, which they quickly
   translated from Greek into Latin and vulgar tongues and began
   teaching in their existing University system (which was already
   300 years old by then), bringing about a popularization of
   humanism and other thoughts to a new generation of students.
   Byzantium was struggling and it was only a few years later that
   it fell completely to Mehmet II, marking the end of an era for
   one intellectual culture yet thanks to the last-minute transfer
   of knowledge, brought about the start of another. Had Byzantium
   not falling to a "let's wipe out everything and do it right this
   time" mindset (which was new to Islamic education and began the
   start of the Ottoman empire), it's very likely that the East and
   West would've been able to join together in this new revolution,
   the old educating the new in an ongoing basis. But alas, all the
   West had were some books given right at the end of the Eastern
   Roman Empire and we've done the best we can with them ever
   since, shaping the course of Europe for centuries to come. We're
   still picking up the historical pieces and some of our
   misreadings of history have yet to be improved, but I think a
   lot of that has to do with an England-centric view of history
   that we've inherited since the 19th century.