The Holy See, in the Polish lands, permanently granted the privilege of purple vestments in the 18th and 19th centuries, lending splendor to certain metropolitan capitals: Gniezno, Mogilev and Warsaw. The granting of such an exception was linked each time to the issuance of papal documents. This happened for the reason that the aforementioned metropolitans were not granted cardinal dignity. The case of the Mogilev metropolitan archbishops is connected with the efforts of Archbishop Stanisław Siestrzeńcewicz to obtain membership in the College of Cardinals. Eventually, the Holy See exclusively granted the privilege of purple vestments to Archbishop Stanisław Siestrzeńcewicz and his successors. Owing to the contacts of Jan Kazimierz Wilczyński with the Parisian studios, lithographic portraits were created in the 19th century capturing the splendour of the Metropolitan Archbishops of Mohilev. The Museum of Archdiocese of Warmia in Olsztyn stores chromatic images of the two archbishops and is the object of the following study.