Detail of the vault of the Chapel of St Sebastian in St Peter’s, Rome,cartoon

Detail of the vault of the Chapel of St Sebastian in St Peter's Rome from around 1633 is a cartoon by Pietro da Cortona for one of the most prestigious decorative commissions in Roman Baroque art. Working in St Peter's placed Cortona at the pinnacle of papal patronage, contributing to the great Baroque transformation of the world's largest church that engaged virtually every major Roman artist of the period. Cortona was the supreme master of Roman High Baroque decoration, whose ceiling fresco for the Gran Salone of the Barberini Palace defined the illusionistic ceiling painting that dominated European decorative art for a century. These large-scale cartoons were essential working drawings for transferring compositions to fresco at architectural scale. The Nationalmuseum in Stockholm holds this cartoon as a document of Cortona's working process and his contribution to the greatest architectural project of seventeenth-century Rome.

The cartoon demonstrates Cortona's monumental figure style and dynamic compositional approach that would define Roman Baroque ceiling painting.