The treaty addressed the joint English and French reaction to the Sack of Rome (1527) in May 1527 and the imprisonment of Pope Clement VII in the Castel S. Angelo. But the Cardinal de Lorraine had no part in that business. The principal negotiator was the Chancellor, Antoine du Prat. He was, however, one of the four French cardinals who were present at Compiègne on 16 September and wrote, under Wolsey's leadership as Papal Legate, to the Pope, informing him that they were praying for his release from captivity and planned, if the Emperor should not accommodate them, to refuse any papal orders issued under duress. He also witnessed the investing of the Chancellor, Antoine du Prat, with the symbols of the cardinalate which had been granted him by the Pope at the request of King Francis. His growing importance is reflected in a list of precedence of 1528, in which he and the King of Navarre follow immediately after the King.