Half-Section of the Model of the Attic and Dome of Saint Peter's Basilica as Conceived by Michelangelo (recto); Detail Studies Relating to the Plan, Section, and Elevation of the Dome of Saint Peter's Basilica (verso).

1551, 1558–69

Pen and brown ink, over leadpoint or black chalk.

29.8 × 44 cm (11.7 × 17.3 in)