Paintings from antiquity rarely survive—paint, after all, is a much less durable medium than stone or bronze sculpture. But it is thanks to the ancient Roman city of Pompeii that we can trace the history of Roman wall painting. The entire city was buried in volcanic ash in 79 C.E. when the volcano at Mount Vesuvius erupted, thus preserving the rich colors in the paintings in the houses and monuments there for thousands of years until their rediscovery. These paintings represent an uninterrupted sequence of two centuries of evidence. And it is thanks to August Mau, a nineteenth-century German scholar, that we have a classification of four styles of Pompeian wall painting.