Kataban, you've been sucked into an untrue belief about history. Windmills, manufacture of paper, the spinning wheel, magnetic compass, eyeglasses, astrolabes, stern mounted rudders, the horse collar, horseshoes, the wine press, rib vault, chimney, segmental bridge arch, treadwheel crane, stationary harbor crane, floating crane, hourglass and mechanical clocks, water hammers, horizontal loom, hard liquor, glass mirrors, compound crank, blast furnace, rolling mill . . . that doesn't even count the things that they did better than before, like metallurgy and agricultural advances like the 2/3rds field rotation system.
All of these things were invented during the Middle Ages. There was, in fact, nothing like a technological stagnation during the period. Which is why historians have stopped calling it the “Dark Ages”. The "nothing happened during the Middle Ages" was a conceit developed by the Renaissance humanists who wanted to attribute everything good in civilization to the Greeks and Romans. It's just a historical canard that's stuck around for a while.