But it was not till the era of scientific archaeology--which came to Pompeii and Herculaneum with Fiorelli in 1860--that the buried cities began to add their never-ceasing stores to the sum of our knowledge of ancient town-planning, public life, private life in town and country houses, trade and tradesmen, religion, and art. * * * * * [Illustration: FIG. 8.2 Pompeii, air view. (University of Wisconsin Classics Dept. collection)] [Illustration: FIG. 8.3 Pompeii, plan. (MPI)] One of the results of scientific excavation at Pompeii was to reveal at last the town plan (Fig. 8.2), after decades spent in sporadic digging for treasure trove, in cutting paintings out of walls, filling in the excavated houses, and moving on without system to a new area. The plan as now revealed (Fig. 8.3) shows the least regular streets in the southwest quadrant of the town around the Forum; this, therefore, should be the oldest part; and in fact architectural terracottas found here, in the so-called _Foro triangolare_, are dated in the sixth century B.C. Elsewhere the pattern of a rectangular grid is clear, making possible the division of the city for purposes of archaeological reference into nine regions. Each region is subdivided into numbered blocks, or _insulae_; each _insula_ into numbered houses. The whole 160 acres, big enough for a population of from fifteen to twenty thousand, is surrounded by a wall, in which archaeologists, on the basis of building materials and techniques, have detected four phases. The earliest, with a facing of squared limestone, dates from the fifth century B.C.; the latest, marked by the addition of high towers, from the time of Sulla, who settled some of his veterans here in a colony grandiosely named the _Colonia Veneria Cornelia Pompeianorum_. Masons’ marks from the third phase (280–180 B.C.) are in Oscan letters, the alphabet of ancient Italy’s major language, next after Latin and Greek. Inscriptions (street signs for example) show that Oscan persisted as Pompeii’s third language, along with Latin and Greek (for the area around Naples had originally been settled by Greeks, and they kept their culture), down almost to the time of the eruption. The wall shows the marks of the stone catapult-balls of the Sullan siege; some of the balls were found preserved as souvenirs in houses. After the Sullan phase the wall was allowed to fall into disrepair, mute evidence of the security of the Augustan peace. * * * * *