MEDIEVAL AND RENAISSANCE POPES ORCHESTRATED PROCESSIONS AND urban theatricals to serve their political goals just as Rome's imperial rulers had staged public spectacles to manifest their civic power and responsibility. Translating icons and holy remains, receiving foreign dignitaries, staging funerals, and holding public games were all carefully choreographed and codified ceremonies which, like the ritual performance of the mass, reinforced the Church's spiritual authority and buttressed its temporal rule over the city. Moreover, by engaging important churches and palaces along the way, the Church manifested control over particular sites of contention.

The most important procession was the papal possesso, the route of which, weaving through the Campo Marzio along Via Papale, had developed over the centuries into the most important east–west passage in Rome. Occasionally, in times of political tension, the established route was modified to avoid specific locations or to reflect new alliances between the Church and barons; yet the ceremony continued in reduced form, even while the popes were in Avignon (see Chapter 22; Fig. 135).

With renewed papal commitment to Rome in the mid-fifteenth century, the possesso became a vigorous political symbol of the intertwined rebirth of city and Church. But now that the popes resided at the Vatican rather than the Lateran palace, its route was reversed. After being crowned at St. Peter's, the pope, mounted on a white horse and surrounded by his entourage, headed to the Lateran to take possession of his bishopric. Elaborate and ephemeral triumphal arches, decorated with papal insignia, were deployed at key locations along the route (see Fig. 135). Over time the possesso became more splendid – the papal cortege grew larger, the vestments more sumptuous, and the pageantry more elaborate – all in an effort to confirm papal sovereignty over the Christian world, the city government, and the nobility, and to delineate the specific relationships of each body with the pope. Rituals articulating papal control occurred at designated sites along a well-defined route; at Monte Giordano, for example, the pope met with Jewish leaders, while at Piazza S. Marco he tossed coins into the crowd (Fig. 177).