The latest studies into the origin of the architectural and artistic style of the early medieval (Romanesque) churches at Strzelno point to new conclusions with regard to their chronology and the identity of the founder of the Norbertine convent. Detailed analyses show that the form of the Strzelno sculptures bears a close resemblance to the representations on the tympanums and doorposts of the western portal in the Benedictine abbey at Andlau in Alsatia, dated 1160-1180. The acceptance of this chronological reference point for columns with figural personifications of virtues and vices as well as for the foundation tympanum with a relief model of St Prokop's rotund church at Strzelno is further corroborated by the Romanesque architectural sculpture from Saxony, Turingia, Westphalia, Hessen and Bavaria (in the light of the German data the bases and capitals of Strzelno cannot be dated earlier than 1150) and some findings of costume history (the fashion for elongated sleeves came to end in 1180-1200). Stylistic analyses suggest that the other foundation tympanum at Strzelno may be dated to 1180-1190, while the northern portal, with the ogival, trefoil cut of the tympanum archivolt, goes back to the first quarter of the 13th century. Of an earlier date are the columns of the presbytery arcades (which draw on a number of models, including the cubic capitols of the Olbin Abbey in Wroclaw): they seem to belong to the first half of the 12th century. The dating of the origin of the Strzelin sculptures within a timeband extending from the first half of the 12th until the first quarter of the 13th century is supported by ample archaeological and architectural evidence. It indicates that the abbey church was built in stages, beginning with the presbytery, followed by the nave and, in the end, by the western façade. This chronological scheme points to Palatin Piotr Wlostowic as the original founder of the Norbertine convent. After his death in 1151 the construction work was continued by his descendants, the Wszeborowice. The foundation process was finally completed in 1216, when Krystyn Wszeborowic, the son of Piotr, Voivod of Kujawy and Castellan of Kruszwica, had the convent basilica dedicated to the Holy Trinity and the Blessed Virgin Mary „in accordance with the express wishes of the late Piotr [Włostowic]”.