Levels, construction techniques, and artifacts assigned various dates to these buildings, but their earliest phases fall in the Republican period, in the age of Sulla or earlier. To the age of Sulla belongs also a handsome rock-cut theater. There is an amphitheater of the early Empire; as we know from a new inscription, its donor was Macro, the notorious informer under the Emperor Tiberius, who brought about the fall of the Emperor’s ambitious and scheming favorite, Sejanus. Walls, grid, civic center, public buildings: these made of Alba a smaller and more orderly replica of Rome. The general layout is repeated so often in so many places that it suggests a master plan made in the censors’ office in Rome. By the time Cosa was founded, in 273 B.C., the Romans already could draw on the experience of founding at least eighteen colonies. * * * * * Cosa, where the writer did his first excavating, may be used to supply a little more detail on materials and methods in field archaeology. Seven eight-week spring seasons of excavation there (1948–1954), modestly intended as laboratory training for young American classicists, have in fact resulted in a remarkably complete picture of an old-style Latin colony. The site was chosen for excavating because it looked attractive from air photographs, because it was convenient to Rome (ninety miles up the Via Aurelia on the Tyrrhenian Sea), and because its walls were almost perfectly preserved, great gray masses of polygonal limestone looming up as high as a four-story building on a 370-foot hill that rises out of the reclaimed swamplands of the Tuscan Maremma. For Cosa was planted, carved out of the territory of the once proud Etruscan city of Vulci, to mount guard over Rome’s newly acquired marches, and to affirm Rome’s name and supremacy in a restive neighborhood.