Although the first professors at the School of Salamanca were theology ones, it is unquestionable that they made deep reflections about the most essential concepts of metaphysics. They took Summa Theologica as a guide as well as discussed some methaphysics opuscules of Thomas Aquinas, who they followed, but not in a dogmatic or scholastic way. It can be said that they made a critical Thomism reception and they made an effort to find a vivid and effective expression of the real distinction among essence and existence, which is the key in order to understand the relationship among God with creature.