This dissertation explores in the ways in which decorum, or the appropriateness of form and behavior, served as an underlying principle in the patronage, design, and construction of monumental architecture, sculpture, and inscriptions by the aristocratic elite of late antique urban environments. Throughout the dissertation, I deliberately turn my attention away from imperial buildings like Emperor Justinian's (r. 527-565) Hagia Sophia and towards those projects financed by aristocrats and elites, with a focus placed upon those associated with the gens Anicii and their sphere. It is through the discussions of the built environments of Rome, Constantinople, and Ravenna in the fourth through sixth centuries CE, that my dissertation reveals the ways in which aristocrats and elites, like members of the gens Anicii and wealthy bankers like Julianus Argentarius, were able to concretize their power in periods of political change. Their employment of a decorum of architecture, based upon Vitruvian and Ciceronian ideals, demonstrates the central role these individuals played in the shaping of the visual culture of the late antique Mediterranean. It was through the patronage of statues and buildings that were thoughtfully dedicated, strategically located, and purposefully decorated that these wealthy patrons were able to galvanize their non-imperial authority. In historical moments wracked by war, plague, and political instability, the finance and construction of large-scale statuary on prominently inscribed plinths, as well as solid, immovable buildings afforded these elites with a sense of permanence and stability that, they hoped, would last in perpetuity.