The last years of his reign brought defeat during expeditions in support of his Hungarian allies, provoking renewed Bohemian invasions. A group of nobles took advantage of the situation, forcing Bolesław to make a political testament which carved Poland up into duchies. Each of his five sons was to rule over one of these. Pomerania, whose dukes were closely related to but not of the main Piast line, was given equal status. The eldest son, Władysław, was
to reign in the small but theoretically paramount duchy of Kraków as well as his own and exert suzerainty over the others. Thus when Bolesław the Wrymouth died in 1138, the country embarked on a political experiment designed to compromise between regionalist tendencies and an underlying sense of kinship and political unity.
Ironically, considering the frequent interruptions in the succession and the consequent fragmentation of the realm, this sense of unity was based primarily on the Piast dynasty. They had established over eighty castle-towns by the end of the eleventh century and endowed market towns with royal charters granting rights and protection. They encouraged the replacement of barter with their own coinage, and provided the security necessary for the development of international trade routes through the country. Cities such as Kraków, which became the capital in 1040, Sandomierz, Kalisz, Wrocław, Poznań and Płock flourished.
Another unifying element was the Church, which was instrumental in the spread of new technologies and of the Romanesque style in architecture. It was also central to the spread of culture and education, providing as it did technical expertise, administration and schooling for would-be priests and young noblemen. The arrival of the Benedictines, whose monastery at Tyniec on the Vistula dates from the second half of the eleventh century, and later of the Premonstratentian and Cistercian orders, added impetus to this process. Most of the cathedrals had schools attached to them, and through the institution of the Church it was possible for Polish students to travel to other counties in search of learning. A local Latin
A distinction must be drawn between the great impact of the Church’s educational and even political activities, and the con—siderably lesser one it produced at the strictly religious level. Pagan cults survived the official conversion of the country in 966, and the next two centuries witnessed several major revivals, during which churches were burnt and priests put to death. The pagan survivals were particularly strong in areas such as Pomerania, which maintained a measure of autonomy in the face of pressure to submit to either Polish or Imperial overlordship.
The Church could do little about this in the face of a general lack of zeal, which is well illustrated by the Polish response to Rome’s summons to the Crusades. Apart from Prince Henryk of Sandomierz, few heeded it. Duke Leszek the White explained in a long letter to the Pope that neither he nor any self-respecting Polish knight could be induced to go to the Holy Land, where, they had been informed, there was no wine, mead, or even beer to be had. There were other reasons for staying at home, since there were troublesome pagans on Poland’s own frontiers in the shape of the Prussians and Lithuanians. But little was being done to convert them, and this lack of zeal was characteristic. A major motive propelling European knights across the seas to fight crusades in Palestine and the Baltic (and settlers to follow them) was the population explosion of the Middle Ages which produced overcrowding in some areas. The far from populous Poland felt no such need for expansion, and her rulers welcomed the immigration of Jews, Bohemians and Germans who provided useful services.
The realm continued to fragment after the death of Bolesław the Wrymouth in 1138 had transformed it into five duchies. The eldest of his sons, Władysław, made an attempt at reuniting it from his position as ruler of Kraków, but he came up against the resistance not only of his brothers but of most of the local lords as well. Over the next hundred years successive dukes reigning in Kraków proved less and less able to enact the formal suzerainty which went with the position, and eventually abandoned the attempt altogether. The various branches of the royal family established local dynasties, in some cases subdividing the original five duchies of Wielkopolska, Mazovia-Kujavia, Małopolska, Sandomierz and Silesia into smaller units in order to accommodate their offspring.