What was the Byzantine capital?
Transmission of the Greek Classics:  Interest in Greek texts and their availability was scarce in the Latin West until traffic increased to the East, particularly the medieval Islamic world from where Arabic translations were translated to Latin, and the Byzantine Empire during the time of the Crusades and the Latin rule of Constantinople following the sack of the Byzantine capital in 1204 during the Fourth Crusade. Sack of Constantinople (1204): The Sack of Constantinople or Siege of Constantinople occurred in 1204 and marked the culmination of the Fourth Crusade.
Constantinople