Florence was now by far the leading city in Tuscany. Its merchants and money-dealers were in correspondence with every Mediterranean port and with every country of the West. Along with bales of goods and letters of exchange new ideas and fresh intelligence were always on the road to Florence. The knowledge of what was going on in the world, and of what men were thinking, was part of the stock-in-trade of the quick-witted citizens, and they were beginning to be employed throughout Europe in diplomatic work, till then almost a monopoly of churchmen. 'These Florentines seem to me to form a fifth element,' said Boniface, who had ample experience of how accomplished they were. At home they had full employment for their political genius; and still upon the old problem, of how to curb the arrogance of the class that, in place of being satisfied to share in the general prosperity, sought its profit in the maintenance of privilege. It is necessary, at the cost of what may look like repetition, to revert to the presence and activity of this class in Florence, if we are to form a true idea of the circumstances of Dante's life, and enter into the spirit with which much of the _Comedy_ is informed. Though many of the nobles were now engaged in commerce and figured among the popular leaders, most of the greater houses stood proudly aloof from everything that might corrupt their gentility. These were styled the magnates: they found, as it were, a vocation for themselves in being nobles. Among them the true distinctive spirit of Ghibelinism survived, although none of them would now have dared to describe himself as a Ghibeline. Their strength lay partly in the unlimited control they retained over the serfs on their landward estates; in the loyalty with which the members of a family held by one another; in their great command of resources as the administrators of the _Parte Guelfa_; and in the popularity they enjoyed with the smaller people in consequence of their lavish expenditure, and frank if insolent manners. By law scarcely the equals of the full citizens, in point of fact they tyrannised over them. Their houses, set like fortresses in the crowded streets, frequently served as prisons and torture-chambers for the low-born traders or artisans who might offend them.