When's the earliest the accordion can be invented? Wikipedia says it was invented in 1822, also stating it may have been invented earlier. So how early could it have happened? 1700's? 1600's? Medieval?
From 1789 to today, have as many coups, revolutions, overthrows, civil wars, etc. as possible in France. Whether it's Bourbon, Bonapart, Orleanist, Republican, Boulangist, fascist, communist, or whatever it may be.
If the Mongol empire hadn't passed the Urals into Russia and hadn't invaded the middle east and destroyed Baghdad, how would things progress? Would the plague be less devastating? Would Islamic nations be more successful?