This essay aims to reconstruct the political and public dimensions of Christian visual culture in the crucial transition between the third and fourth centuries, in order to frame the memory of Helena Augusta within this process of symbolic appropriation. It is the purpose to understand why the memory of Helena was precisely charged with the role and responsibility of promoting the salvific sign of the cross through its discovery. Through such an inquiry, it will be shown to what extent the political aspect of ancient Christianity fostered the development of the theme of the representability of the divine, in accordance with the symbology of power, in order to demonstrate how the processing of the narratives about the inventio crucis attributed to Helena cannot be understood without considering the development of the visual and devotional needs of Christian power.