1232 Tribunals of the Inquisition established in southern France.
1233 The Germans put to death the first inquisitor.
1234 Rising in Rome drives Gregory from the city.
1238 League of Venice, Genoa, and the pope against Frederick, on account of his growing power and successes in Lombardy.
1239 Excommunication of Frederick and charges preferred against him.
1240 Gregory proclaims a crusade against Frederick, who invades the papal territory.
1241 Frederick’s fleets capture twenty-two Genoese galleys, containing many ecclesiastics on their way to a council at Rome. They are imprisoned. Death of Gregory. Goffredo Castiglione, Celestine IV, elected. He dies in eighteen days. The see is vacant.
1243 Frederick releases some of the imprisoned ecclesiastics that an election may take place. Senibaldi di Fieschi, Innocent IV, is chosen. Peace negotiations fail.
1244 Innocent escapes to Lyons.
1245 Innocent calls the Thirteenth General Council at Lyons. Frederick is excommunicated and deposed.