From a diachronic perspective, and considering both textual and visual evidence, this article traces the relic cult of SS Gregory Nazianzen and John Chrysostom. It focuses on two historical contexts, hitherto not compared with each other, in which both the relics and the architectural frame in which they were placed acquired significant additional meaning and value: tenth-century Constantinople and sixteenth- century Rome. I will show how Emperor Constantine VII, in the Holy Apostles, and Pope Gregory XIII, in St. Peter's, used the same relics as an instrument in a process of meaning-making, thereby asserting their own authority and prestige. [ABSTRACT FROM AUTHOR]