This dissertation considers Michelangelo’s intended sculptural program for the never-realized façade of the Medici parish church of San Lorenzo in Florence, and how its iconography related to the Medici, the Papacy, and the city of Florence. In 1516, Pope Leo X de’ Medici commissioned Michelangelo to complete both the sculpture and the architecture of the façade. This project, which Michelangelo claimed would be the “mirror of architecture and sculpture of all Italy,” was to be the most prestigious commission of the sixteenth century and Michelangelo’s most ambitious creation. But, for the Medici patrons, the sculptural program for the façade would have been the ultimate expression of Medici propaganda. Chapter one is a study of the history of San Lorenzo and generations of Medici patronage at their parish church. The sculptural program for the façade would have visually communicated the Medici dynasty and their destiny, and thus, the account of the San Lorenzo façade project starts here. Chapter two provides an overview of the façade commission and Michelangelo’s involvement on the project from 1516 to 1520. Chapter three is dedicated to Michelangelo’s architectural façade drawings for San Lorenzo, and his figural drawings for statuary that have been previously unassigned to a known project or connected to his other sculptural projects. These drawings are considered afresh in conjunction with the vast extant correspondence from this period, with the primary focus on Michelangelo’s concern for the sculptural decoration of the façade. Chapters four and five use the methodologies of iconography and iconology to reconstruct the intended plan for the sculptures on the façade. Michelangelo greatly enlarged the original sculptural program from ten over-life-sized marble statues, to eighteen freestanding over-life-sized marble and bronze statues, and nineteen relief panels. This expanded sculptural program relied on a calculated arrangement of the saints and their placement on the façade, which had specific meanings and connotations for the Medici, for Florence, and for the Medici in the papal court in Rome. Appendix A of the dissertation is a detailed chronological account of the façade project as extrapolated and compiled from more than three-hundred extant letters.