After the eleventh century, when the Communes were formed, the building of the fortress was less frequent, and the Communal Palace took its place. The guild was always gradual in its adoption of new styles, and the palace of the Podestà or the "Signoria" differed only in form, and not in style, from the older castle. There is the same solid masonry--either _opus Gallicum_ of smoothly-hewn stones fitted with nicety, or _opus Romanum_ of flat wide bricks welded together with cement till they are strong as a Roman wall. There are the same battlements and cornice of arches supported on brackets; and wherever a window is needed, high enough to be safe without an iron grating, it is invariably of the old Lombard form, with its two round arches enclosed in a larger one. There was the same pillared courtyard with its flight of steps to the upper floor. Jacopo Tedesco's Bargello at Florence, his Castle at Poppi, and his Palazzo Pubblico at Arezzo are the most beautiful examples of this style. [Illustration: CAPITAL OF A COLUMN IN THE DUCAL PALACE, VENICE. _See page 253._] Arnolfo's Palazzo Vecchio, the Palazzo of the Commune at Siena, and the Palazzo Pubblico at Pistoja show the next step towards a less military style. There still remains much of the fortress, in the solidity and rigidity of the masonry below, and the battlemented lines above, but the tower is no longer a solid weapon of war; it becomes an airy ornamental shrine for a peaceful civic bell, that rings for the joys and sorrows of the people.