The Forma Urbis Romae, or map of the city of Rome, was a massive plan of the layout of the city under the emperor Septimius Severus (r. A.D. 193–211). Although only a small portion of the plan survives, scholars are relatively certain it illustrated most of the city. This fragment shows commercial structures on the southeastern slope of the Viminal Hill. The Forma Urbis adorned the wall of a room in Rome’s Temple of Peace that might have served as an archive of maps and records. Drawn at a scale of 1:240, the plan resembles a land surveying map, in that it includes not only streets and blocks, but also interior features of buildings, such as colonnades and staircases. However, its monumental size—60 feet by 43 feet—suggests a decorative rather than practical function, says archaeologist Susann Lusnia of Tulane University. “The Forma Urbis provided an overview of the changes made to Rome by Severus in his quest for legitimacy and establishment of his dynastic succession,” she says. “The marble plan was itself a monument to the Severan legacy in Rome.” Severus’ ambitious building program included both restoration of older monuments and creation of new ones as part of his effort to draw attention to his nascent dynasty.