 About three months later , he met Emperor Frederick 's son Henry in Metz and visited Henry 's guardian , Engelbert , Archbishop of Cologne . From Germany John went to southern Italy , where he persuaded Pope Honorius to allow Emperor Frederick to postpone his crusade for two years . Frederick married John 's daughter , Isabella ( who had been crowned queen of Jerusalem ) , on 9 November 1225 . John and Frederick 's relationship became tense . According to a version of Ernoul 's chronicle , John got into a disagreement with his new son @-@ in @-@ law because Frederick seduced a niece of Isabella who was her lady @-@ in @-@ waiting . In the other version of the chronicle John often " chastised and reproved " his son @-@ in @-@ law , who concluded that John wanted to seize the Kingdom of Sicily for his nephew Walter IV of Brienne and tried to murder John ( who fled to Rome ) . Frederick declared that John had lost his claim to the Kingdom of Jerusalem when Isabella married him ; he styled himself king of Jerusalem for the first time in December 1225 . Balian of Sidon , Simon of Maugastel , Archbishop of Tyre , and the other Jerusalemite lords who had escorted Isabella to Italy acknowledged Frederick as their lawful king . 
 About three months later , he met Emperor Frederick <a href='null_genetive' title='1'><mark>'s</mark></a>son Henry in Metz and visited Henry <a href='null_genetive' title='2'><mark>'s</mark></a>guardian , Engelbert , Archbishop of Cologne . From Germany John went to southern Italy , where he persuaded Pope Honorius to allow Emperor Frederick to postpone his crusade for two years . Frederick married John <a href='null_genetive' title='3'><mark>'s</mark></a>daughter , Isabella ( <a href='null_relcl' title='4'><mark>who</mark></a><a href='been_done' title='5'><mark>had</mark></a> been crowned queen of Jerusalem ) , on 9 November 1225 . John and Frederick <a href='null_genetive' title='6'><mark>'s</mark></a>relationship became tense . According to a version of Ernoul <a href='null_genetive' title='7'><mark>'s</mark></a>chronicle , John got into a disagreement with his new son @-@ in @-@ law because Frederick seduced a niece of Isabella <a href='null_relcl' title='8'><mark>who</mark></a>was her lady @-@ in @-@ waiting . In the other version of the chronicle John often " chastised and reproved " his son @-@ in @-@ law , <a href='null_relcl' title='9'><mark>who</mark></a>concluded that John wanted to seize the Kingdom of Sicily for his nephew Walter IV of Brienne and tried to murder John ( <a href='null_relcl' title='10'><mark>who</mark></a>fled to Rome ) . Frederick declared that John <a href='been_done' title='11'><mark>had</mark></a> lost his claim to the Kingdom of Jerusalem when Isabella married him ; he styled himself king of Jerusalem for the first time in December 1225 . Balian of Sidon , Simon of Maugastel , Archbishop of Tyre , and the other Jerusalemite lords <a href='null_relcl' title='12'><mark>who</mark></a><a href='been_done' title='13'><mark>had</mark></a> escorted Isabella to Italy acknowledged Frederick as their lawful king . 
Abt three months later , he met Emperor Frederick  son Henry in Metz and visited Henry  guardian , Engelbert , Archbishop of Cologne . From Germany John went to southern Italy , where he persuaded Pope Honorius to allow Emperor Frederick to postpone his crusade for two years . Frederick married John  daughter , Isabella ( done been crowned queen of Jerusalem ) , on 9 November 1225 . John and Frederick  relationship became tense . According to a version of Ernoul  chronicle , John got into a disagreement with his new son @-@ in @-@ law cuz Frederick seduced a niece of Isabella was her lady @-@ in @-@ waiting . In da other version of the chronicle John often " chastised and reproved " his son @-@ in @-@ law , concluded that John wanted to seize tdaKingdom of Sicily fir his nephew Walter IV of Brienne and tried to murder John ( fled to Rome ) . Frederick declared that John done lost his claim to the Kingdom of Jerusalem when Isabella married him ; he styled hisself king of Jerusalem for the first time in December 1225 . Balian of Sidon , Simon of Maugastel , Archbishop of Tyre , and thdather Jerusalemite lords done escorted Isabella to Italy acknowledged Frederick as their lawful king .