With development of long-range trade in the Middle Ages, a new type of commerce sprang up - temporary markets, visited by both local and foreign visiting merchants, and also by other men whose trade flourishes in crowds of people (such as jugglers and thieves). These events quickly prove their importance for both trade and culture - in such places commodities are exchanged, but so are ideas, music, books and other stuff. So, they become a necessary step to later development of human sciences.