 After signing the treaty , John returned to Sulmona . According to the contemporary Matthew Paris , he allowed his soldiers to <unk> nearby monasteries to obtain money . John lifted the siege of Sulmona in early 1229 to join Cardinal Pelagius , who launched a campaign against <unk> . Frederick II ( who had crowned himself king of Jerusalem in the Church of the Holy <unk> ) returned to Italy , forcing the papal troops to withdraw . 
