At the beginning of the viceregal era, the Certosa di San Martino, a Carthusian monastery of medieval foundation, experienced a resurgence that culminated in the rebuilding of its church starting in the late 1580s. The new church of the Neapolitan Certosa featured an innovative design and an extensive and complex decorative program that distinguished it from all other churches of the order. This dissertation examines the rebuilding of the church of the Certosa di San Martino as a process deeply rooted in the changing religious culture of the time and one that also reveals the tensions inherent to the redefinition of monastic identity in Post-Tridentine Spanish Naples. The development of the Carthusian project paralleled the institutional re-organization of the order, but it also assumed a unique trajectory aimed at highlighting the role of the white monks and contemplative spirituality in the production of sanctity in Naples. By tracing the evolution of the rebuilding initiative within its proper cultural, religious and social context, I clarify the goals of the patrons and the expectations placed on the artists, and I define the scope of the project according to new parameters of spiritual authority. The reconstruction of the rebuilding process relies on primary sources from the Neapolitan State Archives and on recent historical and archaeological research, in addition to comparative studies. This dissertation challenges the view of Post-Tridentine monastic architecture as a mere response to the new liturgical requirements and sides with more recent interpretations by seeing monastic sacred spaces as dynamic places of exchange, and their designs and decorations as expressions of the spiritual authority of the monastic body they house. The rebuilding of the church of the Certosa di San Martino stands as an important example of the process by which spiritual authority was produced and redirected in Spanish Naples. Since 1973, when the first and only monograph on the art of the Certosa di San Martino was published, studies have been sporadic and limited to the analysis of particular works contained in the church. I analyze the new architectural plan and decoration of the church as fundamentally bound to the transformation of Spanish Naples into a holy city. / Art History