Yet, let us suppose that Hellenism sank to the most horrible madness, sucrificing its own children to the new faith: how then this same ‘alienated’ hellenism, studied, loved and saved its ancient self all those centuries? 

Byzantium searched with passion for the ancient texts, all the ancient manuscripts, it copied them in thousands. This restored the ancient Greek works, the text that we read today. It accomplished this huge work with remarkable care, in order to remain as close as possible to the initial text, it created a tradition of critical editing which continued the Alexandrian tradition of the Hellenistic era. Without the bibliographical workshops (scriptoria), without the Byzantine editors [mostly monks] whose activity surprises us, to what would have been limited our collection of ancient texts that we call classical?” (-Paul Lemerle, The continuity of the European Conscience). 

Cf. The Transition of Hellenism from Antiquity to Christianity  / Greek Orthodoxy – From Apostolic Times to the Present Day  / The Ancient Greeks (text in Greek only)