Guides to the monuments of Rome appeared regularly from the thirteenth century onward. A notable description was written by the poet Petrarch (Francesco Petrarca, 1304–1374), who first visited Rome in 1337 and who collected, studied, and wrote about ancient inscriptions and coins. Such interests were, of course, normal for the educated classes in the early Renaissance, and collections of antiquities were commonplace among the great families, who often had their seats in imperial monuments. In Rome, for example, the Orsini family occupied the Mausoleum of Hadrian (Castel Sant’Angelo, later a papal fort), the Colonna family had the Baths of Constantine, and the Frangipani family fortified the Colosseum and the Arch of Titus.

The greatest of these noble families, the Medici, had their base in Florence. Cosimo the Elder (1389–1464) began the family’s collection of antiquities, which was greatly expanded by Lorenzo “the Magnificent” (1448–1492). Competition between the aristocratic families and the papacy for ancient works of art became intense from this period on. Already there was concern for the fate of ancient monuments, particularly in Rome, as expressed by a papal bull issued by Pius II (r. 1458–1464) that threatened excommunication for those taking marble from Roman ruins. Stone from Roman monuments was disappearing at an astounding rate in the fifteenth century; under one of Pius’s immediate predecessors, Nicholas V, over 2,500 cartloads of travertine were removed from the Colosseum by one contractor in one year. The ban, however, was honored more in the breach than the observance, and Pius’s own ledgers record how he rebuilt the steps of Saint Peter’s Cathedral with stone from the Colosseum. He was, though, a remarkable pope, who seems to have organized the first “systematic” excavation—an attempt to recover two large Roman ships submerged in Lake Nemi. The work was undertaken by the artist-architect Leon Battista Alberti (1404–1472), adviser to a number of popes between the 1430s and 1470s and author of a newly professional topographical work on ancient Rome, the Descriptio Urbis Romae (ca. 1440). The excavation of the Nemi ships was only partially successful. Their full excavation was undertaken by the Fascist government in the 1920s, and the level of the lake was lowered to reveal two enormous pleasure barges belonging to the emperor Caligula. (These were later burned by retreating troops in 1944.)

A number of important works of ancient art had never been buried—particularly coins and gemstones but also some large-scale sculptures, such as the equestrian statue of Marcus Aurelius on the Capitoline, the Capitoline She-Wolf, and Lo Spinario, all in bronze. These three statues were among those in the papal collection given by Pope Sixtus IV (r. 1471–1484) to the city of Rome in 1471. They were housed in the Palazzo dei Conservatori on the Capitoline Hill, which became the world’s first public museum (the Musei Capitolini). Sixtus IV also forbade the unauthorized excavation of antiquities, which were beginning to flood out of Rome and sites such as Hadrian’s Villa at Tivoli. This edict also had little effect; in the late fifteenth and early sixteenth centuries, excavations proliferated. Among the most notable was the discovery of the Domus Aurea (the Golden House of Nero) in central Rome. Part of this palace was discovered on the Oppian Hill, covered by the foundations of the later Baths of Titus; systematic visits to the underground chambers began around 1480. The style of wall painting seen there was immediately influential on contemporary wall painting (and the fantastic figures borrowed from these artificial grottoes, known as grottesche, are at the root of our word grotesque).

Many Roman monuments were ransacked during the sixteenth century, and perhaps more ancient sculpture was discovered in this century than in any other. Works such as the Laocoon, discovered in the Baths of Trajan in 1506 and seen immediately by Michelangelo, had a profound effect on contemporary artists. Typical of the period was the excavation of the enormous Baths of Caracalla, particularly under Paul III (r. 1534–1549), where teams worked in search of building material and ancient sculptures. A number of well-preserved works were discovered, such as the so-called Farnese Hercules and