Answer:
Europe, after very difficult centuries during the early middle ages, began to flourish again in the high, and especially, the low middle ages.
Several factors contributed to this progress. To start, political stability improved. Several states consolitated political power over particular areas, by implementing the system of feudalism in the case of the Kingdom of France and England, and a city-state system in the case of Italy.
More political stability brought more wealth because this incentivized investement and trade. For example, Italian city-states like Venice and Genoa, became wealthy thanks to the trade networks that they built once the cities themselves became politically stable.
