In his first relection on the ecclesiatical power (I DPE), delivered in 1532, Vitoria posed the set of problems of the origin, essence, and juridical foundations of ecclesiastical authority. In the introduction to his text, he defined the notion of a church as an assembly of faithful Christians, or, and this is extremely important, as a Christian Commonwealth (Respublica christiana). The first part of the relection was dedicated to the definition of the essence of the ecclesiastical authority. According to Dominican Theologist, the Church, besides possessing civil power (potestas), has another type of authority (auctoritas) which is concentrated and located in the Church keys. These keys, passed by Jesus Christ to his apostles, have the exceptional force of giving the complete absolution of sins, and to open the doors of Heaven’s Reign. The next questions of the I DPE were dedicated to the juridical origins of ecclesiastical power and to its limits in respect to civil authority. As well, Vitoria described some of the peculiarities of the Church’s jurisdiction.