After having usurped the episcopal see of Salona for seven years against the will of Gregory the Great, Maximus returned to obedience and received the pallium, granted by the Pontiff with a reminder of its value as a symbol of justice and humility. Praefectus Urbi, and later supreme pontificate, Gregory knew well the labyrinths of power and the arduous and constraining paths those who, at the pinnacle of the Christian hierarchy, are tasked to adhere to as servus servorum Dei. That these involve extraordinary difficulties is obvious a priori, and, in the case of our Pontiff, is documented and described with extraordinary wealth of detail in the correspondence bearing his name. On the basis of this documentation, this essay aims to show that Gregory felt humilitas, as Bishop Maximus was reminded, to be the surest bastion against continuing danger to the unity of the Church in every circumstance, whether the title of universality, claimed by more than one patriarch, or the ambitions to wear episcopal sandals by the deacons of Catania. Big or small, every form of pride must be considered pernicious to unity among those called to follow Christ. Obstacles are overcome even more successfully the Pope insists if humilitas is reinforced as thoughtful and lived in an eschatological prospect, that is, in the spiritual condition in which time and the eternal feel joined, avoiding the lacerations and conflicts that devastate the world. This mutual and indelible virtue creates the strongest bonds between the followers of Christ, thus rendering them servi servorum Dei.