This essay considers the significance of foundation ceremonies in the western Christian church, paying special attention to Saint Peter’s basilica in Rome (refounded 1506) and two Venetian votive churches: the Redentore (begun 1577) and Santa Maria della Salute (begun 1631). At the ceremonial foundation of the new Saint Peter’s the sensory impact helped to commit the Church hierarchy to the continuation of the project. Built to mark Venice’s deliverance from the plague, Palladio’s church of the Redentore and Longhena’s church of Santa Maria della Salute were state-funded commissions enacted by solemn vows of the Venetian Senate. The essay describes how rich arrays of sensory stimuli ensured the future significance of the rituals in Venice’s festive calendar through the infusion of shared memories. These two ceremonies were communal acts of purification to signal the elimination of plague and prevent future pestilence.