 The crusaders laid siege to Damietta , on the Nile , in May 1217 . Although they seized a strategically @-@ important tower on a nearby island on 24 August , Al @-@ Kamil ( who had succeeded Al @-@ Adil I in Egypt ) controlled traffic on the Nile . In September , reinforcements commanded by Pope Honorius III 's legate Cardinal Pelagius ( who considered himself the crusade 's supreme commander ) arrived from Italy . 
 The crusaders laid siege to Damietta , on the Nile , in May 1217 . Although they seized a strategically @-@ important tower on a nearby island on 24 August , Al @-@ Kamil ( <a href='null_relcl' title='1'><mark>who</mark></a><a href='been_done' title='2'><mark>had</mark></a> succeeded Al @-@ Adil I in Egypt ) controlled traffic on the Nile . In September , reinforcements commanded by Pope Honorius III <a href='null_genetive' title='3'><mark>'s</mark></a>legate Cardinal Pelagius ( <a href='null_relcl' title='4'><mark>who</mark></a>considered himself the crusade <a href='null_genetive' title='5'><mark>'s</mark></a>supreme commander ) arrived from Italy . 
Da crusaders laid siege to Damietta , on the Nile , in May 1217 . Although they seized a strategically @-@ important tower on a nearby island on 24 August , Al @-@ Kamil ( done succeeded Al @-@ Adil I in Egypt ) controlled traffic on tdaNile . In September , reinforcements commanded by Pope Honorius III  legate Cardinal Pelagius ( considered himself the crusade  supreme commander ) arrived from Italy .