The article presents the history of the cult of the state patron from the royal dynasty, and the sources and prototypes of the worshipping tradition of the holy rulers. Furthermore, the article seeks to answer the question whether the circumstances that had shaped the cults of the holy rulers in the 10th -12th and 16th -17th centuries could cause immense differences in the hagiography as well as iconography of the rulers, and analyses the ways in which the cult of Saint Prince Casimir of the Early Modern Times is similar to related medieval holy rulers. Political development of Lithuania during the 14th century was very similar to the growth of pagan states during earlier centuries. The Hungarians was the last Central European nation to have converted to Christianity. From the point of view of acceptance of Christianity in Hungary, the cult of St. Stephen was developing under the circumstances similar to the Lithuanian worshipping tradition of St. Casimir. The Christian world received the news that with the help of St. Casimir Catholicism took roots in the state where the seed of the Evangel had only recently sprouted. Baroque hagiography of St. Casimir took over the virtues that had been highlighted throughout the Middle Ages. The images, rhetoric figures and symbols that had taken shape in the Middle Ages were again emphasized, reiterated and used in his worshipping tradition. The article seeks to reveal the way how the worshipping of Prince Casimir acquired the features typical of state patrons, and how his cult integrated into the tradition of devotion to European holy rulers.