Baroque Rome was not planned in a day: forms of immunity in Alexander VII’s and Louis XIV’s urban strategies (1656–68)

In the seventeenth century, Rome’s urban territory was legally contested, particularly during the 1660s when the Popes sought to assert power over the foreign states’ territorial claims. The papacy’s influence on the urban landscape was traditionally marked by extensive building activities that bolstered its financial resources, despite a decline in temporal power evidenced by diplomatic failures in the mid-1600s. Ecclesiastical immunities and privileges were employed as legal tools to generate income and reclaim urban territory, while European powers pursued ambassadorial extraterritoriality. Two crises, the 1656–1657 plague and the expansion of Louis XIV’s diplomatic immunities, exposed papal authority, prompting Pope Alexander VII to use architecture to reformulate his political aims. This paper argues that the concept of ‘immunity’ is key to understanding the significant urban and architectural forces that shaped Rome’s Baroque city.