 After signing the treaty , John returned to Sulmona . According to the contemporary Matthew Paris , he allowed his soldiers to plunder nearby monasteries to obtain money . John lifted the siege of Sulmona in early 1229 to join Cardinal Pelagius , who launched a campaign against Capua . Frederick II ( who had crowned himself king of Jerusalem in the Church of the Holy Sepulchre ) returned to Italy , forcing the papal troops to withdraw . 
 After signing the treaty , John returned to Sulmona . According to the contemporary Matthew Paris , he allowed his soldiers to plunder nearby monasteries to obtain money . John lifted the siege of Sulmona in early 1229 to join Cardinal Pelagius , <a href='null_relcl' title='1'><mark>who</mark></a>launched a campaign against Capua . Frederick II ( <a href='null_relcl' title='2'><mark>who</mark></a><a href='been_done' title='3'><mark>had</mark></a> crowned himself king of Jerusalem in the Church of the Holy Sepulchre ) returned to Italy , forcing the papal troops to withdraw . 
After signing da treaty , John returned to Sulmona . According to the contemporary Matthew Paris , he allowed his soldiers to plunder nearby monasteries to obtain money . John lifted the siege of Sulmona in early 1229 to join Cardinal Pelagius , launched a campaign against Capua . Frederick II ( done crowned himself king of Jerusalem in tdaChurch of the Holy Sepulchre ) returned to Italy , forcing the papal troops to withdraw .