What about medicine? The leap from Galen (whose methods dominated Europe for a shockingly long time) to Islamic-era methods was pretty dramatic. You have the in

What about medicine? The leap from Galen (whose methods dominated Europe for a shockingly long time) to Islamic-era methods was pretty dramatic. You have the invention of modern surgical methods in Cordoba in the 10th century (many still used), use of antiseptics to clean wounds, general elevation of evidence-based methods for pharmacology, rise of teaching hospitals, etc.. Medicine doesn't necessarily shift the borders of empire but it does dramatically affect the quality and duration of a typical person's life. The difference between being born in the 6th century vs. the 11th would (to us) I think be painful brutal existence vs. civilization.