The little building just across the way was the Guild House of the Arte della Lana, or Wool-combers, and is now the head-quarters of the Italian Dante Society, who hold a conference every Thursday in the large room over Or San Michele, gained by the flying buttress-bridge. The dark picture on the outer wall is the very Madonna to which, when its position was at the Mercato Vecchio, condemned criminals used to pray on their way to execution. Before we leave Or San Michele and the Arte della Lana, a word on the guilds of Florence is necessary, for at a period in Florentine history between, say, the middle of the thirteenth century and the beginning of the fifteenth, they were the very powerful controllers of the domestic affairs of the city; and it is possible that it would have been better for the Florentines had they continued to be so. For Florence was essentially mercantile and the guilds were composed of business men; and it is natural that business men should know better than noblemen what a business city needed. They were divided into major guilds, chief of which were the woollen merchants--the Arte della Lana--and the silk merchants--the Calimala--and it was their pride to put their riches at the city's service. Thus, the Arte della Lana had charge of the building of the cathedral. Each of the major guilds provided a Prior, and the Priors elected the Signoria, who governed the city. It is one of the principal charges that is brought against Cosimo de' Medici that he broke the power of the guilds. Returning to the Via Calzaioli, and turning to the right, we come very quickly to the Piazza della Signoria, and see before us, diagonally across it, the Loggia de' Lanzi and the Palazzo Vecchio, with the gleaming, gigantic figure of Michelangelo's David against the dark gateway. This, more than the Piazza del Duomo, is the centre of Florence. The Palazzo Vecchio was for centuries called the Signoria, being the home of the Gonfalonier of Florence and the Signoria who assisted his councils. It was begun by Arnolfo, the architect of the Duomo and S. Croce, at the end of the thirteenth century, that being, as we have seen, a period of great prosperity and ambition in Florence, but many alterations and additions were made--by Michelozzo, Cronaca, Vasari, and others--to bring it to what it now is. After being the scene of many riots, executions, and much political strife and dubiety, it became a ducal palace in 1532, and is now a civic building and show-place. In the old days the Palazzo had a ringhiera, or platform, in front of it, from which proclamations were made. To know what this was like one has but to go to S. Trinità on a very fine morning and look at Ghirlandaio's fresco of the granting of the charter to S. Francis. The scene, painted in 1485, includes not only the Signoria but the Loggia de' Lanzi (then the Loggia dell' Orcagna)--both before any statues were set up.