Established after the year 1000, the diocese of Poznań embraced the territory of Western and South-Western Wielkopolska proper. Neither their soils nor population density made that stretch of land in any way attractive. The unpromising beginnings did not, however, prove to a serious hindrance to the subsequent population growth and the onset of the urbanization processes. In the estates of the Poznań bishops a phase of intense economic growth began in the middle of the 13th and continued until the end of the following century. The increase in the number of episcopal landed estates round some conveniently situated settlements was followed by the upgrading of the latter into municipal centres (Pszczew, Dolsk, Krobia, Słupca, Ślesin, Śródka, and Buk). In time all of them developed into local trade centres and acquired their own parishes; five of them (Pszczew, Dolsk, Krobia, Ślesin, and Buk) were also administrative centres of the church estates. Situated along the major routes from Wielkopolska to Germany, Pomerania, Kujawy and Silesia, the episcopal towns were in a good position both to add to the volume of long-range and local trade as well as to profit from it. Among the Poznań bishops who pioneered the economic growth of the episcopal latifundium and founding of new towns were Bogufał of Czerlino (1255-1265), Jan II Herbicz (1286-1297), Andrzej Zaremba (1297-1318) and Jan V Doliwa (1356-1374).
Of the seven episcopal towns one was incorporated by the middle of the 13th century (Śródka), three in the second half of the 13th century (Buk, Pszczew and Słupca), and three in the 14th century (Krobia, Dolsk and Ślesin). Some links between the new towns and earlier settlements can be traced in the case of Śródka, Pszczew and Krobia. While Buk was sited not far from the prince's court, the pre-incorporation settlements of Słupca, Ślesin and Dolsk had already had a connection with traffic, markets and toll gates. For their livelihood the residents of those towns depended primarily on farming and to a lesser extent from on trade and manufacturing. Only four of them continued to grow and developed into more important economic centres: Słupca advanced into the second class of Wielkopolska towns in the middle of the 15th century (1458), while Buk, Dolsk and Krobia made their way into Class Three. The remaining local centres never sloughed off their village character; their incorporation charters were later revoked.