It's entirely random, and has nothing to do with the non-European world, but here's how I would do it ... for fun:
235 to 1000: Early Middle Ages, vernacularisation of Latin culture, spread of Christianity everywhere between Ireland and Rus, development of cities in northern and eastern Europe, and so on.
1000 to 1348: High Middle Ages, population growth, specialisation of the economy to the degrees elsewhere in Eurasia, differentiation between Roman and Orthodox Christianity, growth of government, and so on
1348 to 1556: Breakdown of Latin Christianity, development of autocracy, spread of gunpowder, printing technology, vernacularisation of elites, discovery of new world, replacement of Roman Empire by Ottomans, and so on