Meanwhile, the English king's possessions in France were coming under threat from the French king. Charles IV of France demanded that Edward again pay homage for his Duchy of Aquitaine, while at the same time threatening to confiscate the duchy under the pretext of a local dispute involving the priory at Saint-Sardos. In April 1324, Edmund and Alexander de Bicknor, Archbishop of Dublin, were sent to France on a diplomatic mission. While some historians have criticised Edmund for his failure to reach a diplomatic settlement, others have pointed to the difficult circumstances he faced, and how others had fared little better. When diplomacy failed, Edmund was appointed Edward's lieutenant in Aquitaine on 20 July 1324. Though there was a desperate need for reinforcements from England, these never arrived. In the short war that followed, the English lands were quickly overrun by the French, and Edmund was besieged at La Réole. Here he held out until 22 September, at which point he was forced to surrender and agree to a six-month truce.