He defines the axes of differentiation using Vitruvius" descriptions of public v. private and grand v. humble spaces. Initially, Wallace-Hadrill describes, in the public and grand axis, that while house size was a clear indication of status, architecture and decoration played an equally integral role in denoting wealth and dignitas. He goes on to discuss how the spectrum of status around the house was displayed through certain techniques. Wallace-Hadrill has two main points. First, a wealthy owner would desire to create an allusion of being in a public space. This was employed architecturally through the use of primarily columns and room shapes such as curved walls, curved ceilings, and apsidal ended rooms. This was also achieved through a variety of artistic devices in wall-painting as well. The effect of wall-paintings evolved over time and used the effects of color, motifs, and frameworks. .
Wallace-Hadrill's second point was the "articulation of the house," which is how different social groups were guided around the house. The first group is visitors, and the compositional significance is expressed through the degrees of access permitted to these outsiders. Of intra-domus importance was the differentiation of areas for the second group, the slaves. The structural influence on these two groups was derived by exploring a variety of methods, including decoration style and the subtle use of architecture, such as narrow hallways denoting servile use. Through the exploration of guest and servant movement through the house, Wallice-Hadrill is able to trace an evolution during Roman history in the use of space and in how that was articulated. His argument is that as the Empire grew, the aristocracy conveyed a stronger desire to protect themselves and seclude into a private life of luxury, away from the influence of the slaves.
Focusing on Wallice-Hadrill's first argument, the wealthy imitating public buildings can be understood because it was these public spheres that the successful Roman citizen exercised power.
