To date, the glazed pottery from Chelm dating to the reign of Prince Daniel Romanowicz has been no more than mentioned in archaeological literature. It was commonly believed to be an import from Rus territories. The said group has been dated with considerable precision to the period between 1240 and the last decade of the 13th century. On site no. 144, identified as a habitation and production settlement associated with the princely castle on 'Wysoka Gorka', a total of 347 fragments of glazed pottery from the period has been discovered. Adding the finds from 'Wysoka Gorka' to the old-town sites and the settlement in Chelm-Bielawin gives us the largest quantity of early mediaeval glazed pottery known from anywhere in Polish territory, thus putting Chel in the same category with leading Rus centers, such as Lubec, Grodno, Mstislavl', Cernichov and others. Laboratory studies of the glazed pottery from Chelm were carried out under a scanning microscope and spectrophotometer of X-ray fluorescence. The objectives included determining the degree of homogeneity of the set of glazed pottery, identifying the composition of the pottery matrix and glazes, and developing the best research methods for the purpose. A total of 14 different vessel sherds and a piece of floor tile were studied. All in all, 98 analyses were carried out; of these, 47 concerned the chemical composition of the glaze, 51 the ceramic matrices. A series of photographs of the objects in question were taken on this occasion. Evidence for the local production of glazed pottery is provided by the considerable quantities of sherds, but also by finds of local cooking pots accidentally covered with the glaze on the surfaces and breaks. Some vessel forms, especially pots, constitute additional evidence, as they are close in style to the majority of 13th-century vessels found in Chelm. Equally so, there seems to be a homogeneous stylistic conception that shaped the majority of vessels in all the categories. Chelm also appears as a center of developed glass artisanship, involved in the production of glass ornaments and the glazing of ceramic tiles. Testifying to this are the quantities of finds connected with this branch of the industry, including crucibles used in glass melting and slag. One of the vessels can be attributed to the oldest glazed-pottery horizon and could be an import from Rus territory. In this case the decoration technique is for the 13th century archaic, and there are differences in the chemical composition of the glaze on this vessel. Characteristic features of glazed pottery include: execution using rolls of clay in the kneading technique, outer vessel surface glazing, bottom included and the use of kaolin clays for the manufacture of green-glazed vessels. Local clays were used for vessels covered with brown glaze, fired to brick-red or gray-brown. The ornamental importance of glazes is confirmed by the specific choice of the areas for glazing, which included only the visible and easily accessible surfaces. The glazing was executed by pouring a thin glaze melted in the crucibles onto the surface of the already fired vessel. This process was possible owing to the application of glazes made according to a lead-silicon formula, containing high levels of litharge (ca. 70%). An XRF spectrophotometer combined with scanning microscope was used to examine the chemical composition of the glazes. A point analysis of fresh breaks of the glaze was found to provide the best results. Numerous corrosive eruptions were noted on the surface of the glaze along with a thin layer of changed chemical composition. Thanks to the high selectiveness of this method for spot analysis, surface changes of the glaze occurring before the discovery of the object can be determined. The glaze on Chelm vessels was observed to have changes in the surface layer, characterized by an elevated content of calcium, phosphorus and iron oxides, and a lowered content of lead oxide. This is most likely due to the specific conditions of deposition of the objects from Chelm. Most features containing numerous iron finds (ready-made products and half-products connected with metallurgical activity) and organic remains (bones) are sunk into the chalk bedrock. By making more analyses of a single sample it was possible to determine the differences in the chemical content of a single glaze. The silty fraction and particular components of the detritus fraction were analyzed separately for the ceramic matrix. It was also found that the best way for preparing a sample for analysis was to cut the sample from the ceramic matrix in the direction of the glaze. In this way it was possible to avoid polluting the ceramic matrix with the melted glaze penetrating into the pores of the clay and solidifying as granules. On the grounds of the analyses, it was discovered that the glazed vessels were made of the same material as the other pottery from Chelm. Material used with particular frequency included alluvial fen soils, the characteristic properties of which is the presence of rounded quartz grains and indeterminable minerals rich in iron. Kaolin clays were also used, these being more difficult to obtain. The assortment of glazed vessels is rich. The largest quantity of sherds represents big jugs with a single handle, heavily bulging body and funnel-like rim. Numerous sherds were identified as fragments of small bowls. Much less frequent were fragments of pots, bigger bowls and pans. The closest parallels, morphologically and technologically, for the vessels from Chelm are the finds from Ukraine and Belarus; this is in all likelihood connected with the arrival, confirmed by the Hipacki latopis, of artisans from these regions to Chelm. Yet in style these vessels also refer to finds from territories under the influence of the material culture of Byzantium. The glazed vessel finds from Chelm and many other Rus centers refer, with regard to the form, to numerous objects generating from, among others, the area of present-day Bulgaria (e.g. Silistra, Pliska) and the Apennine Peninsula, yet dated considerably earlier, from the fall of Antiquity. The glazed vessels from this region are on the whole completely different in morphology and style from Slavic pottery (especially the bowls, small bowls and jugs). The farther away from the territories of the Eastern Empire, the later this pottery appears and the more it differs in terms of techniques used in its production. Glazed vessels were used primarily at the princely court or else belonged to the richer inhabitants of the settlement around the castle in Chelm. In the future, glazed pottery should become the object of in-depth studies which will broaden our knowledge of this little known group of objects.