behalf of the pope. On 10 November, Gregory gave Cardinal John of Colonna the power to absolve Frederick of his excommunication. The same day he informed hi ally, the Lombard League, that he had opened negotiations. On 11 November, he wrote to Frederick formally expressing his desire to accept him back into the church and make peace. Thomas and John were the main papal negotiators. The letters and registers of Thomas are an important source for the process. Even so, he frequently refers to information that could only be shared orally. Frederick's negotiators were the Teutonic grand master Hermann von Salza, Archbishop Lando of Reggio and Archbishop Marinus of Bari. The negotiations were protracted, with embassies moving back and forth between the papal and imperial courts. Rains, however, left the roads in a poor state, impeding travel. In February 1230, the Lombard League object to the negotiations. In March, Thomas informed Gregory that Frederick might give him what he wanted if he only lifted the excommunication immediately. In the end, the German princes intervened on behalf of Frederick to save the negotiations. In April 1230, however, to prevent him from taking part in the negotiations, Gregory renewed the excommunication of Rainald of Urslingen, who had led the invasion of the Papal States. In May 1230, the papal representatives were prepared to lift Frederick's excommunication if the emperor only recognized papal possession of Gaeta and Sant'Agata dei Goti. He refused. A formula acceptable to both parties was finally agreed on 9 July. Terms According to the terms of the peace, Frederick's excommunication would be lifted and all other papal acts against him canceled. A general amnesty was to be issued to those who had supported the pope. Exiles were permitted to return. The properties of the Templars and Hospitallers that Frederick had confiscated were to be returned, as were any lands he had seized from the Roman church. Frederick surrendered his traditional legatine authority over the Sicilian church, agreeing to free ecclesiastical elections and exempting the clergy from secular courts, taxes and tallages. Frederick would recognize the independence of the Papal State. The status of Gaeta and Sant'Agata would be resolved by further discussion or arbitration within twelve months, leaving the pope with certain rights over two cities in the Sicilian kingdom. As a guarantee, the papacy would retain control of certain Sicilian castles until the execution of the treaty. The