When 19th century Christendom shifted its allegiance from a divine vertical authority to the horizontal revolutionary ideals of egalitarian democracy, Dom Gueranger's masterpiece contributed more than any other contemporary work to uphold papal authority in all of its divinely ordained prerogatives.
This labor of the holy abbot helped to restore in Catholic Europe the spiritual sword, as well as the magisterial cathedra, to the Vicar of Christ the King. And he did so simply by appealing to the simplicity and clarity of the Gospels, universal Christian tradition, and the common sensus fidelium.
The brilliant hypothetical scenario, drawn by the author, of a college of a dozen apostles, called by Christ, but without a Cephas (Rock) in Peter and his successors, presents the infant "collegial" church in an unenviable plight!
Although written to oppose the errors of the Gallicans and those who opposed the definition of papal infallibility at Vatican I, this work is just as useful today as that same error has resurfaced in our times as collegiality.
You have rendered an extremely useful service to the Church by undertaking to refute the main proposition (of the Gallican conciliarists), and by demonstrating their hostile, impetuous, and contrived character; you have accomplished this with such solid arguments, such brilliance, and such an abundance of evidence drawn from sacred antiquity and ecclesiastical science, that 'conveying many things in few words' you have proved empty the pretense of wisdom of those who have wrapped their opinion in ignorant talk." (Brief of Bl. Pope Pius IX to Dom Gueranger concerning the publication of The Papal Monarchy)