Lombards and Franks at Pavia, the incursions of Huns and Saracens, the kingdom of the Normans at Palermo, formed but accidents and moments in a national development which owed important modifications to each successive episode, but was not finally determined by any of them.  When the Communes emerge into prominence, shaking off the supremacy of the Greeks in the South, vindicating their liberties against the Empire in the North, jealously guarding their independence from Papal encroachment in the center, they have already assumed shapes of marked distinctness and bewildering diversity.  Venice, Milan, Genoa, Florence, Bologna, Siena, Perugia, Amalfi, Lucca, Pisa, to mention only a few of the more notable, are indiscriminately called Republics.  Yet they differ in their internal type no less than in external conditions.  Each wears from the first and preserves a physiognomy that justifies our thinking and speaking of the town as an incarnate entity.  The cities of Italy, down to the very smallest, bear the attributes of individuals.  The mutual attractions and repulsions that presided over their growth have given them specific qualities which they will never lose, which will be reflected in their architecture, in their customs, in their language, in their policy, as well as in the institutions of their government.  We think of them involuntarily as persons, and reserve for them epithets that mark the permanence of their distinctive characters.  To treat of them collectively is almost impossible.  Each has its own biography, and plays a part of consequence in the great drama of the nation.  Accordingly the study of Italian politics, Italian literature, Italian art, is really not the study of one national genius, but of a whole family of cognate geniuses, grouped together, conscious of affinity, obeying the same general conditions, but issuing in markedly divergent characteristics.  Democracies, oligarchies, aristocracies spring into being by laws of natural selection within the limits of a single province.  Every municipality has a separate nomenclature for its magistracies, a somewhat different method of distributing administrative functions.  In one place there is a Doge appointed for life; in another the government is put into commission among officers elected for a period of months.  Here we find a Patrician, a Senator, a Tribune; there Consuls, Rectors, Priors, Ancients, Buonuomini, Conservatori.  At one period and in one city the Podesta seems paramount; across the border a Captain of the People or a Gonfaloniere di Giustizia is supreme.  Vicars of the Empire, Exarchs, Catapans, Rectors for the Church, Legates, Commissaries, succeed each other with dazzling rapidity.  Councils are multiplied and called by names that have their origin and meaning buried in the dust of archaeology.  Consigli del Popolo, Credenza, Consiglio del Comune, Senato, Gran Consiglio, Pratiche, Parlamenti, Monti, Consiglio de’ Savi, Arti, Parte Guelfa, Consigli di Dieci, di Tre, I Nove, Gli Otto, I Cento—­such are a few of the titles chosen at random from the constitutional records of different localities.