In that year an important change was effected in the Constitution.  The whole population of Florence consisted, on the one hand, of nobles or Grandi, as they were called in Tuscany, and on the other hand of working people.  The latter, divided into traders and handicraftsmen, were distributed in guilds called Arti; and at that time there were seven Greater and five Lesser Arti, the most influential of all being the Guild of the Wool Merchants.  These guilds had their halls for meeting, their colleges of chief officers, their heads, called Consoli or Priors, and their flags.  In 1266 it was decided that the administration of the commonwealth should be placed simply and wholly in the hands of the Arti, and the Priors of these industrial companies became the lords or Signory of Florence.  No inhabitant of the city who had not enrolled himself as a craftsman in one of the guilds could exercise any function of burghership.  To be scioperato, or without industry, was to be without power, without rank or place of honour in the State.  The revolution which placed the Arts at the head of the republic had the practical effect of excluding the Grandi altogether from the government.  Violent efforts were made by these noble families, potent through their territorial possessions and foreign connections, and trained from boyhood in the use of arms, to recover the place from which the new laws thrust them:  but their menacing attitude, instead of intimidating the burghers, roused their anger and drove them to the passing of still more stringent laws.  In 1293, after the Ghibellines had been defeated in the great battle of Campaldino, a series of severe enactments, called the Ordinances of Justice, were decreed against the unruly Grandi.  All civic rights were taken from them; the severest penalties were attached to their slightest infringement of municipal law; their titles to land were limited; the privilege of living within the city walls was allowed them only under galling restrictions; and, last not least, a supreme magistrate, named the Gonfalonier of Justice, was created for the special purpose of watching them and carrying out the penal code against them.  Henceforward Florence was governed exclusively by merchants and artisans.  The Grandi hastened to enrol themselves in the guilds, exchanging their former titles and dignities for the solid privilege of burghership.  The exact parallel to this industrial constitution for a commonwealth, carrying on wars with emperors and princes, holding haughty captains in its pay, and dictating laws to subject cities, cannot, I think, be elsewhere found in history.  It is as unique as the Florence of Dante and Giotto is unique.  While the people was guarding itself thus stringently against the Grandi, a separate body was created for the special purpose of extirpating the Ghibellines.  A permanent committee of vigilance, called the College or the Captains of the Guelf Party, was established.  It was their function to administer