The plan of Ostia (Figs. 10.1 and 10.2) is regular but not regimented. It has unity in variety; it combines utility, a monumental quality, and the scenic. Its backbone is the major east-west street, the _decumanus_, nearly a mile long, and once colonnaded, which runs from the Porta Romana straight to the Forum. Beyond the line of the west _castrum_ wall it forks sharply to the left, ending at the Porta Marina, which once fronted directly on the sea. The main north-south street, the _cardo_, began at the Porta Laurentina on the south--Ostia’s triplicity of gates is an Etruscan heritage--and ran, shaded and porticoed, northwestward to the dazzling whiteness of the colonnaded, marble-enriched Forum. Then it split in two on either side of Hadrian’s Capitolium and passed north between balconied houses to the river. Sixteen per cent of Ostia’s total area, exactly the same proportion as a modern city such as Madison, Wisconsin, was devoted to streets. Twelve per cent of Ostia was taken up by baths, fifteen per cent by warehouses (for Ostia was first and foremost a commercial town), and fifty-seven per cent by houses, most of which are middle-class apartment blocks. Knowing the total housing area available, and calculating twenty-six square meters of space for each person, Calza reckoned the maximum population at 35,000 to 40,000. [Illustration: FIG. 10.1 Ostia. (G. Calza, _Scavi di Ostia_, 1)] [Illustration: FIG. 10.2 Ostia, air view. (H. Kähler, _Rom und seine Welt_, Pl. 199)] The evidence for Ostia’s municipal life comes mostly from inscriptions, over 6000 of them, many unpublished. They show that Ostia, like most Italian towns, imitated Rome: since Rome had a pair of chief municipal officers, the consuls, Ostia had a pair also, the _duoviri_. There was a town council of 110 members, which met in a marble-floored council house facing the Forum. Legal activity went on across the street in the basilica, also paved with marble, and with a pleasant portico facing the Forum. It had a charming frieze of Cupids carrying garlands. Both buildings are of Trajanic date; the prevalence of marble in them can be explained by the ease with which the stone could be brought by ships in ballast. There was a municipal plutocracy, whose names occur and recur on honorific decrees (praising them for benefactions), and on tombs near the Porta Romana and Porta Marina. The names are those of businessmen and freedmen, not of the old Roman aristocratic families. And as the years wear on men seldom hold office more than once, for it grew to be an expensive honor. If taxes assessed by the Imperial treasury were not collected in full, town officers had to make up the deficit out of their own pockets.