On 27 September 1427, San Bernardino delivered one of his thundering sermons on the Piazza del Campo in Siena. As was customary with his preaching style, he dotted the sermon with local Sienese references, which, in this instance, included a colourful metaphor about the relative roles of the city cathedral and of its main charitable institution:

The hospital that San Bernardino evokes in his sermon is Santa Maria della Scala, which, as he implicitly suggests through his eye metaphor, was one of the key civic institutions of medieval and Renaissance Siena. The hospital, as the passage indicates, occupied vast premises in front of the city cathedral and episcopal residence. Founded in the eleventh century, by Bernardino’s times the hospital was equipped with its own church, dedicated to the Virgin Annunciate, and prided itself on a set of precious relics and reliquaries of the Passion of Christ, of the Virgin Mary, and of saints. This holy collection was largely the result of a single acquisition made in Venice in 1359, when Santa Maria della Scala purchased an illustrious group of relics and reliquaries of Byzantine provenance from the merchant Pietro di Giunta Torrigiani. By 1427, when Bernardino delivered his sermon, the Byzantine relics had become the focus of a major and well-established public cult in Siena, contributing to the prestige of Santa Maria della Scala and to its civic status. But how was the integration of the Byzantine treasury into the highly specific Sienese civic cult achieved, what purposes did the Byzantine relics fulfil in Siena, and what correlations existed between their use in the Italian city-state and their original meaning in Byzantium?