Meeting of Ferentino and the plan for the Sixth Crusade

Background

Frederick II had taken the cross in 1215 but kept postponing his crusade because of his affairs in Germany and Sicily. After the Fifth Crusade's failure the papacy criticised the emperor's delay. King John of Brienne of Jerusalem, after the death of his wife Queen Maria, was ruling on behalf of his daughter Isabella (Yolanda) and was looking for a powerful ally.

The meeting

At the meeting in Ferentino in March 1223, mediated by Hermann von Salza, it was proposed and agreed that the widowed Frederick II marry Isabella, heiress to the throne of Jerusalem. The marriage would give the emperor a direct claim to the Kingdom of Jerusalem.

Frederick asked for a two-year postponement to complete preparations and promised to set out in summer 1225. John of Brienne believed he would keep the title of king even after the marriage.

Outcome and significance

Frederick married Isabella at Brindisi in November 1225 and immediately proclaimed himself king of Jerusalem, rejecting John of Brienne's claims. This made John the emperor's enemy and the papacy's ally. By the agreement of San Germano in 1225 the crusade was postponed to August 1227; Frederick accepted excommunication if he did not depart by then.

Ferentino marks the beginning of the passage of the crown of Jerusalem to the Staufen dynasty and the binding of the Kingdom of Jerusalem to imperial politics in the following decades.

Sources and debates

Information on the meeting comes from the papal registers, the chronicle of Richard of San Germano and the continuations of Ernoul. Who proposed the marriage, and whether John of Brienne was promised that he would keep the title of king, are disputed.