‘Adhereat lingua mea faucibus meis si non praeposuero Ierusalem in capite laetitiae meae’. Gerolamo d’Ascoli, l’impresa d’Oltremare e la legazione ad graecos (1272)

The 1272 mission to Constantinople of Jerome d’Ascoli, Minister General of the Friars Minor and future pope Nicholas IV , represents an interesting observation point to investigate the relationship between papal diplomacy and the negotium crucis at the end of the so-called ‘classic’ period of the medieval crusades. It allows to understand not only the Gregory X’s international politics, at the threshold of the Second Council of Lyons, aiming at building a Mediterranean Pax, but also its connection with the problem of the unio between the Eastern and Western Churches. In this historical context, in fact, a political and ecclesial Pax constituted the necessary condition for resuming the suspended project of the passagium Terrae Sanctae which is, in turn, the most pressing concern of the Gregorian papacy.