Three Studies of Angels for a Pendentive (recto); Studies for Christ Meeting His Mother on the Road to Calvary, Studies of an Angel in a Pendentive (verso)

Roncalli employed linear draftsmanship with subtle tonal gradations to explore anatomical foreshortening and drapery flow. His approach prioritized structural clarity over atmospheric effects; while sfumato was practiced in Florence, his style here leans toward precise contouring and rhythmic line, suited to mosaic translation. The multiple studies reveal iterative refinement of pose and spatial orientation.

Commissioned by Pope Clement VIII following the dome’s completion in 1590, the mosaics were entrusted to Roncalli due to his Florentine training and reputation for disciplined draftsmanship. This drawing likely originated in his Roman studio during the early phase of the project. Its survival suggests it was retained as a working record, not discarded after execution.

The decoration of Saint Peter’s dome marked a late Renaissance effort to harmonize Michelangelo’s architecture with devotional imagery. Roncalli’s role reflected a broader trend of assigning mosaic work to painters trained in drawing, bridging fresco traditions with the demands of tessellated surfaces. His studies align with Counter-Reformation priorities: clarity, emotional resonance, and doctrinal precision.

Though the mosaics themselves are now partially obscured by time and restoration, Roncalli’s preparatory drawings remain key to understanding the transition from Renaissance draftsmanship to Baroque monumental decoration. This sheet exemplifies the meticulous planning behind papal commissions and the enduring value of preparatory work in large-scale sacred art.