“The development of Orthodox worship was completed in Byzantium, i.e., of that Rule which completes it and makes of it a system permitting almost no progress or change: the Byzantine typikons and euchologia of the 13th and 14th centuries already hardly differ from our own missals and rule-books. The Orthodox icon is painted in accordance with the Byzantine canon, our canonical tradition was fixed in both volume and interpretation by Byzantine canonists, in Byzantium there took final shape that list of the Fathers which has hitherto been the basis of Orthodox theology and, finally, in this period there first flowered that manner and spirit of piety which is well expressed in Russian by the word tserkovnost [churchness].”
(Fr Alexander Schmemann+, ‘Byzantium, Iconoclasm and Monks’)