The fortifications of Pompeii stand as the ancient city’s largest, oldest, and best preserved public monument. Over its 700-year history, Pompeii invested significant amounts of money, resources, and labor into (re)building, maintaining, and upgrading the walls. Each intervention on the fortifications marked a pivotal event of social and political change, signaling dramatic shifts in Pompeii’s urban, social, and architectural framework. Although the defenses had a clear military role, their design, construction materials, and aesthetics reflect the political, social, and urban development of the city. Their fate was intertwined with that of Pompeii.