The “knowledge transfer” debt is supposed to exist because, between the 8th and 10th centuries, a large number of classical Greek writings were translated into Arabic and were “preserved” this way. Later these were translated from Arabic into Latin.
Around 1000 A.D. Scandinavia saw momentous changes: the previously Viking-ruled areas organized themselves into kingdoms—Denmark, Norway and Sweden—and embraced Roman Catholic Christianity as religion.
Across the Gulf of Bothnia, Finland stayed behind in these developments …
Europe pulled itself out of its “Dark Ages”, by its own effort. A number of “renaissances” during the Middle Ages were important mile stones in this development.