The treaty with the Ayyubids was set to expire in 1239. Plans for a new crusade to be led by Frederick came to nothing, and Frederick himself was excommunicated by Gregory IX again in 1239. However, other European nobles took up the cause, including Theobald IV, Count of Champagne and King of Navarre, Peter of Dreux, and Amaury VI of Montfort, who arrived in Acre in September 1239. Theobald was elected leader of the crusade at a council in Acre, attended by the most of the important nobles of the kingdom, including Walter of Brienne, John of Arsuf, and Balian of Sidon.