The Vatican is located on the left bank of the Tiber River in Rome, abutting the ancient Circus of Nero, where, according to tradition, Saint Peter, the first pope and the apostle to whom Christ entrusted his ministry, was martyred in 67 A.D. The seat of the Holy See and the pope’s principal place of residence, it is the smallest independent state in the world. In 320–27 A.D., the emperor Constantine built a five-aisled basilica atop the early Christian necropolis that was Peter’s resting place, with a shrine in the apse of the church to mark the location of Peter’s tomb, then as now an important pilgrimage site. By the fifteenth century, the building was in disrepair and more space was needed, and plans were made to repair and expand the church.

The pontificate of Julius II (r. 1503–13), the “Warrior Pope” who donned armor to lead troops in defense of papal lands, would forever change the Vatican. Dynamic but difficult, with an ego matched only by his vision, Julius was one of the great patrons of Renaissance art and architecture. In 1505, he took up the task left incomplete by Nicholas V (r. 1447–55), who had begun an expansion of the apse of Saint Peter’s. The new apse, Julius decided, would house his tomb, an enormous freestanding monument designed by Michelangelo, one of whose drawings for the ill-fated project is preserved in the Metropolitan Museum (62.93.1). Julius soon decided to tear down the Constantinian basilica and rebuild Saint Peter’s entirely, an idea met with opposition from parties who felt that the old church, which had existed almost from the dawn of Christianity, should be preserved. Partly for this reason, the new structure recalls the old: the piers that support the modern dome, for example, rest on the foundations of the Constantinian nave, echoing its width.

Pope Julius appointed the architect Donato d’Agnolo Bramante (1444–1514) to draw up plans for the new Saint Peter’s. Bramante’s plan of 1506 was a Greek-cross design, four arms of equal length around a crossing. A centralized design was common for martyr shrines, but subsequent architects, including Raphael, Antonio da Sangallo the Younger, Baldassare Tommaso Peruzzi, and Michelangelo, either included or rejected plans for a longer nave. The church as built has a longitudinal plan. Bramante’s plan was space-molding architecture whose massive crossing piers and large barrel vaults derived from imperial models. These elements alluded to Rome’s glorious past and suggested both the continuity of the papacy and the church’s triumph over paganism, the architectural inventions of which it appropriated.

At the same time, Julius commissioned frescoes for the interior of the Vatican palace. He asked Raphael to paint four stanze, or rooms, for use as papal offices and reception spaces. One of these, the Stanza della Segnatura, contains Raphael’s famous fresco The School of Athens. Executed in 1510–11, the painting offers a hint of what Bramante’s church interior might have looked like: the rational space, coffered vaults, and suggestion of a pierced drum, while not based on an actual building, all suggest Raphael’s familiarity with Bramante’s designs. The painting depicts an imaginary gathering of Greek philosophers, many rendered as portraits of Raphael’s contemporaries. Plato and Aristotle preside over the group, the former probably painted in the likeness of Leonardo da Vinci. Bramante appears as Euclid, and Raphael appears as himself, listening to a lecture by the astronomer Ptolemy. The Stanza della Segnatura was Julius II’s library, and the frescoes Raphael executed there illustrate the themes of theology, philosophy, jurisprudence, and poetry, themes that reflect the content of the pope’s books. Raphael’s decoration of the stanze continued under Julius’s successor, Leo X (r. 1513–21). The rooms vary widely in subject matter, but invariably stress the pope’s status as Christ’s vicar on earth, the long history of the papacy, and its continuing protection by God.

As Raphael busied himself with the stanze, Michelangelo was just steps away painting the ceiling of the papal chapel known as the Cappella Sistina, or Sistine Chapel (1508–12). The walls had been frescoed from 1481 to 1483 with scenes from the lives of Moses and Christ by Botticelli, Perugino, Ghirlandaio, and others. Michelangelo painted the vault with scenes from the Book of Genesis: the Creation of the world and of Adam and Eve, the Fall and Expulsion from the Garden of Eden, and God’s destruction of the world by the flood. On the lunettes and spandrels Michelangelo painted Christ’s ancestors, while the spaces between the spandrels show the prophets and sibyls who foretold Christ’s birth. Michelangelo’s drawing for one of these, the Libyan Sibyl, is preserved in the Metropolitan Museum (24.197.2). Later, Pope Paul III (r. 1534–49) would take over a commission ordered by Clement VII in the last year of his rule to have the artists fresco the altar wall of the chapel with the Last Judgment. Michelangelo’s apocalyptic vision depicts hundreds of human souls rising from the earth and ascending to heaven or being pulled into hell under the thunderous hand of Christ the Judge, rendered against a blue sky that suggests a dematerialization of the chapel wall.

In 1546, Michelangelo, now seventy-one years old, was named architect of Saint Peter’s, and dismantled some construction of earlier campaigns to return the plan of the basilica, essentially, to Bramante’s original conception. Soaring above the tomb of Peter is the first great dome to be raised on a colonnade. Designed by Michelangelo but not completed until after his death, it crowns the church and floods the sacred space of the crossing with light from its fenestrated drum and lantern. Michelangelo was similarly attentive to the exterior of the church, unifying the structure by using a coupled Corinthian order throughout. The colossal pilasters and strong entablature that articulate the exterior are his design.