The Arch of Septimus Severus in the Roman Forum (built in 203 AD of marble over a travertine core) has been the object of many restorations in between periods of neglect. The innumerable traces on its surface provide precious historical information; these layers had to be studied and graphically recorded before any intervention could be formally undertaken. The Centro di Conservazione Archeologica has carried out the necessary, detailed, computerized graphic survey to be regularly updated by the conservators. Operations of preconsolidation, cleaning and consolidation have taken place. Each phase is reported in detail and the techniques and materials used are listed, along with brand names and proportions. A very careful method of cleaning was to enclose the surfaces in wind-free chambers and nebulize water thus minimizing mechanical friction on the fragile surfaces. For the consolidation phase, care was taken to use crack fillers that would result in an homogeneous appearance. Integration was limited to the structural elements involved with the disposal of rainwater. The final protection phase is still a subject for research and testing.