These laws also decide the strength of the defensive walls of a city. Law IV. gives the trade price of this sort of work; for those built _in massa_, or _per maxa_, the builder shall for every sixty feet be paid in _solidum unum_ (one soldo, a gold coin). Ricci adds--"This _per maxa_ is the same construction which the Greeks and Romans styled _implectans_, _i.e._ conglomerate." They had several kinds of walls, some of brick, others with a base of stone (_nella base a sassi_), like the walls of Milan, which have lasted till now. Luitprand assigns different money for different kinds of work. Thus at times the _Magistri Comacini_ were paid _solidum unum_ for every foot of wall, sometimes _solidum vestitum_, a distinction of soldi which has puzzled commentators very much; some opining that _vestitum_ refers to a coin on which the emperor is represented as regally clad, and others that it means a copper coin plated (_vestito_) with gold. We find also that terra-cotta vases were much used as ornamentation in building. This style was, as we have said, called "a cacabus." Broken vases were adopted in the foundation of large buildings and houses; others, which probably were not perfect enough for household use, were built into the walls and put as ornaments between the arches. The tower of S. Giovanni e Paolo at Rome and the church of S. Eustorgio at Milan are good instances of this style. [Illustration: TOWER OF SS. GIOVANNI E PAOLO, ROME, 12TH CENTURY. (_From a photograph by Alinari._) _page 65._] Here we have another link with ancient Rome. Promis instances an amphora found in the walls of an imperial edifice in Aosta. At the fountain of Egeria, near the Porta Tiburtina in Rome, the walls are full of amphoræ and oil-jars. On the whole these Masonic laws show that the principal scope of the Longobardic architecture was to make strong and lasting buildings. The building of convents were frequent commissions of the Comacines, and in these, as in their churches, they had a set form. A solid framework of walls either of hewn stone, in the Gallic manner, or of brick in the Roman style, and a few beams and planks, were the simple elements of which a convent was composed.