As we have already observed, the position of the Doge in the Republic of Venice was almost purely ornamental. The Doge presided, either in person or by commission through his councillors, at every Council of State; he presided, however, not as a guiding and deliberating chief, but as a symbol of the Majesty of Venice. He is there not as an individual, a personality, but as the outward and visible sign of an idea, the idea of the Venetian oligarchy. The history of the personal authority of the Doge falls into three periods. A period of great vigour and almost despotic power dates from the foundation of the Dukedom, in the year 697, down to the reign of Pietro Ziani in 1172. During this first period, the Ducal authority showed a tendency to become concentrated, and almost hereditary in the hands of one or two powerful families. For example, we have seen Doges of the Partecipazio house, five Doges of the Candiani, and three of the Orseoli. But the rivalry and balanced power of these great families eventually exhausted one another, and preserved the Dukedom of Venice from ever becoming a kingdom. A second period extends from the year 1172 down to 1457, and is marked by the emergence of the great commercial houses, and the development of the oligarchy upon the basis of a Great Council. The aristocracy during this period were engaged in excluding the people from any share in the government, and in curbing and finally crushing the authority of the Doge. The steps in this process are indicated by the closing of the Great Council, the revolution of Tiepolo, the trials of Marino Faliero, Lorenzo Celsi, and the Foscari. The third period covers what remains of the Republic, from 1457 down to 1797. During this period the Doge was little other than the figurehead of the Republic; the point of least weight and greatest splendour; the brilliant apex to the pyramid of the Venetian constitution.
So far, then, we have examined the four tiers in the original structure of the constitution, the Doge, the College, the Senate, and the Great Council; and we have seen that, broadly speaking these were, respectively, ornamental, initiative and executive, legislative, and elective. But this pyramid of the constitution was not perfectly symmetrical; its edges were broken. This interruption of outline was caused by the Council of Ten. The exact position in the Venetian constitution occupied by this famous Council, and its relations to the other members of the government, have proved a constant source of difficulty and error to students of Venetian history. Leaving aside the obscure problem of the origin of the Ten, it is still possible for us to indicate the constitutional necessity which called that Council into existence. As we have pointed out, the College could not act on its own responsibility without the Senate; the Senate could not initiate without the College, for the preparation of all affairs passed through the hands of the College. To establish connection between these two branches of the administration was a process that required some time; it could not be done swiftly and secretly. In all crises of political importance, whether home or foreign, some instrument, more expeditious than the Senate, was required to sanction the propositions of the College. That instrument, acting swiftly and secretly, with a speed and secrecy impossible in so large a body as the Senate, was created with the Council of Ten. The Ten were an extraordinary magistracy, devised to meet unexpected pressure upon the ordinary machine of government. The emergence of the Ten proves this view. Without determining whether the Council existed previous to the year 1310, we may take that year as the date of its first appearance as a potent element in the State. The rebellion of Tiepolo and Querini, an aristocratic revolt against the growing power of the new commercial nobility, paralysed the ordinary machinery of State, and revealed the danger inherent in a large and slow-moving body of rulers. The Ten were called to power, just as the Romans created the Dictatorship, in order to save the State in a dangerous crisis.