What was the primary reason for the beginning of urbanization in the 11th century?

The primary reason for the beginning of urbanization in the 11th century was the revival of trade and economic prosperity in Europe, particularly following the end of the Viking invasions and the stabilization of feudalism. This led to increased agricultural productivity, surplus food, and the growth of markets, prompting people to move from rural areas to towns for better economic opportunities. As trade networks expanded, towns became centers of commerce, culture, and governance, further accelerating urban development.