There is the apparent assumption running through this thread that the period between the fall of the Western Roman Empire in 476 AD and the rise of Medieval Europe in the 12th-13th centuries was one of unmitigated barbarity with a loss of most if not all classical knowledge in western Europe; that a reboot of civilization awaited the reintroduction of classical knowledge preserved in the Islamic east.
The Eastern Roman, or Byzantine, Empire centered in Constantinople remained a repository of classical knowledge until its fall in 1453. The Church, western and Orthodox, with its monastic tradition, remained a repository of classical knowledge through this entire period. In other words, the knowledge was always there and little if any was actually imported from the Islamic east that wasn’t already there. What was lacking in this period was the settled civil society which finally took root in the western half of Europe in the 12t-13th centuries which would capitalize on the knowledge never really lost.
Preservation of classical knowledge by the early Islamic world is properly lauded. The assertion that the rise of Western European civilization is predicated on preservation of knowledge by Islamic scholars is dubious.
