The most logical and systematic statement of the imperial theory was that of Dante Alighieri (1265-1321 ). Dante had considerable experience in the politics of his city (Florence); and in his wanderings from city to city and from court to court during his long exile, he gained valuable knowledge and experience.
He was interested chiefly in the restoration of peace and unity to Italy, and his De Monarchia was a Ghibelline pamphlet directed against the pro-papal Guelfs. Like other medieval writers, Dante believed that man must live under universal control, either imperial or papal; and he believed that imperial control was preferable in secular affairs.
Although his ideals of a secular world empire and his method of reasoning and of combining classic philosophy, history, civil and canon law, theological dogma, and mythical analogies were distinctly medieval, he revealed traces of the modern idea that the state should exist for the sake of the individual and that the individual should have a share in its management.
In the first part of his work, Dante argued that monarchy is the rightful form of government, because man’s best interests demand peace, and peace is possible only under a single ruler, the human counterpart of God. Cities, nations, and kingdoms should be governed by a ruler common to them all, with a view to their peace.
However, Dante’s emperor was not a universal despot, but a sort of international overseer, whose duty it was to decide contentions among the rulers of the various principalities and cities and to keep the peace among them. National independence and individual freedom were to be maintained as far as possible within the limits of the universal state.
Dante believed that a single monarch, having no rival to dread, and no further ambition to satisfy, could have no motive to rule otherwise than justly. His monarch was Plato’s heaven-born statesman transferred from the Greek city to the European empire.
In the second part of the De Monarchia, Dante cited the Psalmist, Aristotle, Cicero, Vergil, and Aquinas to prove that the Roman victories were considered formal trials by battle in which the judgment of God was manifest; and the fact that Christ was condemned to death by a Roman official was used to justify the righteousness of Roman world rule, otherwise the doctrine of the atonement would be based on an illegal penalty.
Dante argued that perfect peace existed only under the Roman emperors, that the destruction of Roman world unity was followed by anarchy and confusion, and that the restoration of a universal authority was therefore essential.
In the third part of the pamphlet, Dante considered whether imperial authority is derived immediately from God, or indirectly from God through his vicar, the pope. He attacked in true medieval fashion the arguments upon which the advocates of papal supremacy depended, many of his minute refutations being scarcely less grotesque than the arguments themselves.
Dante held that man’s nature, being twofold, demands two guides, emperor and pope. Both received their authority from God, but the emperor is supreme in all that pertains to the secular world. The two species of authority are distinct and the pope has no right to share in the imperial power.
Aside from his clear and condensed statement of the theory of medieval empire, the chief interest in Dante’s work is the proof it offers that peace was considered the vital need of the age. The quarrels of petty princes and the turbulence of the Italian cities had become unendurable. The growth of trade also demanded security. Henceforth political literature emphasized the reasonableness of peace. This idea underlay the later work of Marsilius and stimulated the efforts of the group of jurists whose ideas concerning international regulation were finally crystallized by Grotius.