Granted that Rome was not built in a day, the unresolved question among scholars has been just how long did it take. How early, before Julius Caesar came, saw and conquered, did Romans begin adopting a monumental architecture reflecting the grandeur of their ambitions?

Most historians agree that early Rome had nothing to compare to the sublime temples of Greece and was not a particularly splendid city, like Alexandria in Egypt.

Any definitive insight into the formative stages of Roman architectural hubris lies irretrievable beneath layers of the city’s repeated renovations through the time of caesars, popes and the Renaissance. The most imposing ruin of the early Roman imperial period is the Colosseum, erected in the first century A.D.

Now, at excavations 11 miles east of Rome’s city center, archaeologists think they are catching a glimpse of Roman tastes in monumental architecture much earlier than previously thought, about 300 years before the Colosseum. They have uncovered ruins of a vast complex of stone walls and terraces connected by a grand stairway and surrounded by many rooms, a showcase of wealth and power spread over an area more than half the size of a football field. They say this was most likely the remains of a public building in the heyday of the city-state Gabii, or possibly an exceptionally lavish private residence....