What 2 significant event occurred during middle ages?

Answer 1

There were an awful lot more than two. Arguably the two biggest were one right at the start -- the fall of the Roman Empire, which destroyed Europe's political structure -- and one at the tail end: the Great Plague, which killed between a third and half of the population. In between you have some fairly important ones: Charlemagne's conquest and re-unification of Europe, the Papal Revolution of the eleventh century, for instance.