This chapter is devoted to the pontificate of John VIII (872–882) and the significant physical threat to the city of Rome posed principally although not exclusively by Muslim marauders from North Africa, particularly in the aftermath of the death of Emperor Louis II in 875. Papal efforts to find new military champions were largely unsuccessful, although a significant victory was scored by the Byzantine imperial fleet at the mouth of the Tiber in 880. John VIII also constructed fortifications to defend the church and monastery of San Paolo fuori le mura, hoping to present a repeat of the sack of 846. Although the papal court is known to have been a hotbed of intellectual activity, little has survived from this era in the way of material culture except for the conversion of the temple of Portunus into the church of Santa Maria de Secundicerio by a senior lay official, Stephen secundicerius. Surviving fragments of its mural decorations reveal the influence of both apocryphal texts about the life of Mary as well as contemporary Byzantine hagiographic literature. This leads to a discussion of the place of origin of certain contemporaneous Byzantine manuscripts which share the same style as the murals, most notably the Paris Sacra Parallela (BnF gr. 923).