The great difficulty with which a critic desirous of rendering a succinct account of this phase of Italian culture has to deal, is the variety and complexity of the subject. It is easy to perceive the unity of the humanistic movement, and to regard the scholars of the fifteenth century as a literary community with well-defined relations to each other. Yet when we attempt to trace the growth of scholarship in all its branches, the peculiar conditions of political and social life in Italy present almost insuperable obstacles to any continuity of treatment. The republics, the principalities, and the Church have each their separate existence. Venice, Florence, Naples, Milan, Rome, Ferrara, form distinct and independent centres, imposing their own specialities upon the intellectual activity of citizens and aliens. The humanists, meanwhile, to some extent efface these local differences, spreading a network of common culture over cities and societies divided by all else but interest in learning. To these combinations and permutations, arising from the contact of the scholars with their patrons in the several States of Italy, is due the intricacy of the history of the Revival. The same men of eminence appear by turns in each of the chief Courts and commonwealths, passing with bewildering rapidity from north to south and back again, in one place demanding attention under one head of the subject, in another presenting new yet not less important topics for investigation. What Filippo Maria Visconti, for instance, required from Filelfo had but little in common with the claims made on him by Nicholas V., while his activity as a satirist and partisan at Florence differed from his labour as a lecturer at Siena. Again, the biography of each humanist to some extent involves that of all his contemporaries. The coteries of Rome are influenced by the cliques of Naples; the quarrels of Lorenzo Valla ramify into the squabbles of Guarino; political animosity combines with literary jealousy in the disputes of Poggio with Filelfo. While some of the most eminent professors remain stationary in their native or adopted towns, others move to and fro with the speed of comets. From time to time, at Rome or elsewhere, a patron rises, who assembles all the wandering stars around himself. His death disperses the group; or accidents rouse jealousy among them, and cause secessions from the circle. Then fresh combinations have to be considered. In no one city can we trace firm chronological progression, or discover the fixed local character which justifies our dividing the history of Italian painting by its schools. To avoid repetition, and to preserve an even current of narration amid so much that is shifting, is almost impossible.