Rome, sacred ground for nearly 3,000 years, and counting

According to legend, Rome was born April 21, 753 BC, when Romulus, the survivor of its feuding twin founders, hitched his plow and furrowed a circular perimeter in the hills above the Tiber River. Everything inside was urbs, city space consecrated by priests who interpreted the will of the gods; everything outside was ager - unhallowed open territory. "We have a city founded by the auspices and augury," Roman historian Livy wrote. "There is not a corner of it that is not full of our cults and our gods."

Rome, in a sense, has been sacred ground right from the start.

To many, Rome is the epicenter of Catholicism, the seat of the Vatican and home to a seemingly infinite number of churches. But in the nearly three millenniums of the city's recorded past, Christianity is but a chapter. Rome has sheltered polytheistic pagans and monotheistic Jews, adherents of Middle...