One of the most visited places in the world, Rome attracts millions of tourists each year to walk its storied streets and see famous sites like the Colosseum, St. Peter's Basilica, and the Trevi Fountain. Yet this ancient city's allure is due as much...

At the turn of the fifteenth century, Rome was in the midst of a dramatic transformation from what the fourteenth-century poet Petrarch had termed a "crumbling city" populated by "broken ruins" into a prosperous Christian capital. Scholars, artists,...