The course of Ecclesiastical Law allows to acquire an adequate knowledge of the principles of the Italian legal order, which bases the discipline of the religious phenomenon, understood both individually and collectively (religious confessions and ecclesiastical organizations). The course provides for a systematic analysis of the rules of the 1948 Republican Constitution expressly devoted to the religious factor (Articles 3, 7, 8, 19, 20) with the case law of the Constitutional Court, which since its very beginning judgments intervened in this specific field with great contributions (eg, the discovery of the principle of secularism). Moreover, the multilevel protection of religious freedom also requires the study of sources of international and community law about it, according to the interpretation given to it by the EDU Court and the European Court of Justice. Understanding and learning these principles aims to stimulate student autonomy in judgment and apprenticeship with respect to some important issues for curricula, which will be examined in a specific way. In particular, the following topics will be discussed: the objections of conscience, the public funding system of religious confessions, ecclesiastical bodies and organizations, and the legal discipline of the "third sector", the civil significance of religious marriage. This discussion also allows to highlight the complex intertwining of pattious law with unilateral law which characterizes the structure of the sources of ecclesiastical law and constitutes its peculiarity.