Animal paw prints discovered on Brunelleschi's Duomo tiles in Florence

During winter maintenance of one of the apsidal chapels surrounding Brunelleschi's dome, a specialized team from the Opera di Santa Maria del Fiore discovered ancient animal footprints on the terracotta tiles. Architect Samuele Caciagli, head of the technical area, explained that the imprints were made by animals walking on the tiles while they were left to dry in the sun before firing. The tiles were produced in the kilns of Impruneta, where Filippo Brunelleschi sourced the material for his dome. This discovery reinforces existing knowledge about the construction of the Duomo dome, which began on August 7, 1420—600 years ago. A biography of Brunelleschi by Antonio Manetti notes that the architect personally supervised tile production at Impruneta. Research coordinated by Margaret Haines and the Opera's historical archive confirmed Brunelleschi chose Impruneta clay for its exceptional quality. The imprints date mostly to the 19th century and include tracks of dogs, cats, weasels, and chickens, as well as crosses, kiln marks, dates, and names from later maintenance. Caciagli noted that while not a groundbreaking discovery, the cataloged traces help date and provenance the interventions and tell stories of animals, lovers, and blessings.