Discuss the causes of the development …

The causes are: 
1. The crusades forced the Christians to travel in foreign lands where they came to know of many new objects of comfort and luxury. The demand for new objects gave a great impetus to trade and industry and let to the rise of towns.
2. The emergence of feudalism was accompanied by the decline of trade and towns but with the gradual decline of feudalism, particularly from the 11th century onward, once again to rise trade and towns.
3. The Rise of the Middle Class towards the end of the Middle Ages also led to the emergence of towns. The economic prosperity of this class helped in the developed of towns.
4. The contact between the East and West encouraged trade and commerce which ultimately led to the establishment of various arts and crafts at different centres. These centres slowly became towns.