What material is primarily used on the exterior of the Theater of Marcellus?

The primary material used on the exterior of the Theater of Marcellus is travertine. This natural stone was favored in ancient Roman architecture for its durability and aesthetic qualities. Travertine is a form of limestone that forms in mineral springs, particularly hot springs. Its use in significant structures like the Theater of Marcellus reflects the Romans' advanced engineering techniques and their preference for local materials, as travertine was readily available in the region near Rome.

The Theater of Marcellus, constructed during the late Republic and completed in 13 BCE, showcases a distinctly Roman style that incorporates travertine into its grand façade, which prominently features arches. The use of travertine not only provides a strong structural support necessary for such a large public building but also lends a sense of elegance and permanence to the architecture. The stone easily takes on detailed carvings, allowing for ornate embellishments that are characteristic of Roman theaters.

In contrast, while marble is often associated with Roman public buildings and monuments, its extensive use in this specific theater is secondary, primarily for specific architectural details rather than the main structure. Granite, known for its hardness, was used in various aspects of Roman engineering but was not the primary façade material for the Theater of Marcellus