The quadratura frescoes commissioned by Cardinal Bernardino Spada in 1634 from Angelo Michele Colonna and Agostino Mitelli for the Salone of his Palazzo Spada in Rome have received astonishingly little attention. This article demonstrates the political significance of the hitherto overlooked role of the Cardinal as the Prefect of Pope Urban VIII’s recently instituted Congregation for Borders for the Salone’s complex decoration. In so doing, it engages not surprisingly with the concept of border. Spada’s alignment with papal politics on borders instigated the visual glorification of special benefactors of the Church, such as the first Christian Emperor, Constantine the Great (r. 306–37), and the first Holy Roman Emperor, Charlemagne (c. 742–814), and the departure from the problematic past of contested historical donations in favor of the Church. The imagery in the Salone Spada responded both to acute contemporary concerns regarding papal authority over temporal matters and to coeval artistic trends by which patrons sought to advertise their intellectual and social status. It aimed to consolidate the cardinal’s establishment in Rome in a fashion that, as suggested here, Bernardino Spada had already envisioned through a portrait by Guercino. The analysis of visual strategies at play in the frescoes, ranging from composition to details as paratext, enriches our understanding about border politics as pertaining to seventeenth-century papal policies.