Papal primacy rests on a single line of scripture: Matthew 16:18, “You are Peter and on this rock I will build my church.” The question of whether or not Christ vested the full authority of the Christian Church to Peter alone allowed secular rulers and reformers alike to dispute the legitimacy of the papal institution. In the period leading up to the opening of the Council of Trent, papal primacy became a fundamental concern. Popes claimed that any threat to their plenitudo potestatis jeopardized the unity of the faith, while their opponents saw it as the main hurdle towards religious and civic autonomy. During this time, a series of ongoing papal commissions beginning with Paul III Farnese (1534-1549) and continuing through the pontificate of Gregory XIII Boncompagni (1572-1585) sourced pictorial content from the Acts of the Apostles and the Life of Peter. These pontiffs were able to legitimize and bolster their authority by investing in Petrine and Pauline imagery that promoted the Apostolic identity of the church at a crucial turning point when the very definition of doctrine was intensely debated. This project traces how a coherent and consistent program for leveraging cultural capital emerged across five decorative programs within the Apostolic Palace: the Pauline Chapel (1542-45/1573-76/1580-85), the Casino of Pius IV (1562-63), a previously unknown series of frescoes for the landings of the palace staircases (1572), the second loggia (c. 1574/75), and the area above the portico of Saint Peter’s Basilica (c. 1575/76). Over the course of forty years, the papacy employed artists such as Michelangelo Buonarroti, Perino del Vaga, Giorgio Vasari, Lorenzo Sabbatini, Federico Zuccaro, and many others to visually concretize these Apostolic-focused narratives. Besides painted programs, the larger visual strategy capitalized on a broader scope of media. This included cope decorations, carved marble reliefs, and papal medals, which helped circulate and solidify the thematic typological associations between the Apostolic age and the Tridentine era. By the end of the sixteenth century, the systematic development of the papacy’s Apostolic identity had taken such a firm hold that it continued with Clement VIII Aldobrandini (1592-1605) in the altarpieces chosen for the small nave of new St. Peter’s Basilica, and with Paul V Borghese (1605-1621) at his eponymously named Pauline Chapel. What emerges from this analysis is the collective organization of a papal identity built around the lived and witnessed experience of the disciples that predates the full expression of a Counter-Reformation ideology. / Art History