Opole-Ostrówek: distribution of houses, streets and open spaces in the twelfth century. under the auspices of the Institute for the History of Material Culture of the Polish Academy of Sciences. Continued to the present under the auspices of the Institute, they have yielded some surprising results, especially regarding the period from the tenth to the middle of the thirteenth century. Furthermore, these investigations have contributed to considerable modifications in opinion as to the beginning of urban settlement on Polish soil and the everyday life of Mediaeval Poles. Early Polish agriculture and animal husbandry, the two main sources of wealth in Poland then as now, are also seen in a new light owing to a host of new discoveries likewise resulting in considerable revision of former concepts. 86 It used to be an accepted thesis that towns developed in Poland during the time of the socalled German colonization, which occurred no earlier than the first half of the thirteenth century. Many historians and archaeologists as well believed that Polish handicrafts began to develop only with the conversion of the country to Christianity - which is to say after 966. Both of these beliefs have now been superseded. Excavations at many sites indicate that the devel-