These comments are concerned with both the character of St Chrystian — a Cistercian, abbot of Łękno in Wielkopolska and the first bishop of Prussia — as well as his mission of bringing Christianity to the peoples of that part of Europe. The author’s intention is to review the past record and the current state of research in this field in the context of long-term objectives, which assume that top priority be given to the filling of some of the most glaring gaps, especially those connected with the material evidence and documentation of the functioning of church institutions in the mission area (ie. their needs, construction projects, and economic basis, as well as the conditions in which they had to operate).This review of the content and scope of the most urgent research objectives has produced the following agenda: 1. identifying the seat or seats of the missionary bishop (including a thorough investigation of their environs). An attempt should be made at finding the remains of the presumed cathedral church, the bishop’s residence and other buildings in the episcopal complex. Systematic archaeological excavations should be started first of all at Grudziądz (especially in the early medieval town area in the vicinity of St Nicolas’s Church) and Zantyr. The latter is said to have been the site of a stone cathedral built by Chrystian and destroyed in 1236 by Henry, the Margrave of Meissen; it is also alleged that its ruins were something of a landmark at least until the 15th century. Next on the list excavations is Chełmno, where the remains of a stone church (its construction seems to have been broken off) from the time of Bishop Chrystian have recently been found by archaeologists. 2. throwing light on the Bishop of Prussia’s efforts to set up Cistercian communities in his missionary territory. Those houses were of two types, of which only one seems to have met the criteria of the Cistercian Rule. Bishop Chrystian sent the appropriate charter to Citeaux in 1242; but his death in 1245 prevented it from being endorsed. The other type of community was probably represented by groups of monks obliged to support the bishop’s missionary activities. These small communities may have functioned at the episcopal residences or in outposts inside the missionary territory. This issue requires further field studies in the historical Prussian provinces and more thorough analyses of the written sources and local onomastic traditions. 3. exploring the nature of Chrystian’s links with his native abbey at Łękno during his missionary activities in Prussia. In particular, it is necessary to find out if, or to what extent, he could count on the backing of the Łękno convent in his construction plans. 4. finding out about the ways of financing the Prussian mission in connection with Bishop Chrystian ’s right to mint his own coins.