in 1234 the new pope gregory ix named capocci "rector" of tuscia (tuscany), as well as "capitano" (commander) of the papal troops. in the same year luca savelli, grandson of honorius iii, forced the pope to flee from rome to umbria. emperor (and king of naples and sicily) frederick ii moved from southern italy with an army to help gregory, joining capocci's troops at montefiascone. savelli's army was besieged in a fortress a few kilometers south of viterbo and, although frederick left the siege in advance, capocci was able to defeat them. frederick's ambiguous behaviour led to his excommunication by gregory four years later, and capocci defended the pope's move with a series of letters and treatises disseminated throughout europe, including the manifesto "ascendit de mare".