Fairs in the monastic estates of medieval Poland were an important element of economic and social life, as monasteries, in addition to their religious function, also acted as local and regional economic centres. In the early Middle Ages, income from fairs was a frequent component of the original endowment of newly founded monasteries, providing them with an income in coins or precious metals. On many occasions, these markets were located outside the monastic estates. Thanks to princely and royal grants and later privileges, monasteries were able to organise fairs and markets on their own estates. Legal and economic changes were accompanied by the development of monastery towns, of which there were 58 in Poland by the mid-16th century. Fairs began to play an increasingly important role at that time. Over time, some of the towns belonging to monasteries managed to obtain the right to organise even several fairs a year. The dates of annual fairs were often correlated with religious celebrations, such as patronal feasts of local parish churches or indulgences.