Equally clear is it that the republican life evolved an amount of expansive commercial energy which at that period could not possibly have taken place under a tyrant. The efforts by which Florence developed her trade and power--efforts made possible by the mere union of self-interest among the commercial class--will compare with any process of monarchic imperialism in respect of mere persistency and success. Faced by the jealous enmity of Pisa, their natural port, and suffering from the trade burdens laid on them by the maritime States while they lacked a marine, the Florentines actually opened up trade communication with China when shut out from Egypt by the Venetians; traded through the port of Talamone when the Pisans barred their traffic; took Provençal and Neapolitan galleys in their pay when the Pisans and Genoese tried to close Talamone; and, after becoming masters of Pisa in 1406, not only established a well-ordered marine, but induced Genoa to sell to them the port of Leghorn. They could not, indeed, successfully compete with the Genoese and Venetians till the fall of the Greek Empire; but thereafter they contrived to obtain abundant concessions from the Turks, while the Genoese were driven out of the Levant. Commercial egoism, in fact, enabled them to tread the path of "empire" even as emperors had done long before them; and they hastened to the stage of political collapse on the old military road, spending on one war of two years, against Visconti, a sum equal to £15,000,000 at the present time; and in the twenty-nine years of struggle against Pisa (1377-1406) a sum equal to £58,000,000.[595] Thus they developed a capitalistic class, undermined in the old way the spirit of equity which is the cement of societies, and prepared their own subjection to a capitalist over-lord. But that is only another way of saying that the period of expansive energy preceded the age of the tyrant, wise or unwise.