 John was the youngest of the four sons of Erard II , Count of Brienne , and Agnes of Montfaucon . He seemed " exceedingly old ... about 80 " to the 14 @-@ year @-@ old George Akropolites in 1231 ; if Akropolites ' estimate was correct , John was born around 1150 . However , no other 13th @-@ century authors described John as an old man . His father referred to John 's brothers as " children " in 1177 and mentioned the tutor of John 's oldest brother , Walter III , in 1184 ; this suggests that John 's brothers were born in the late 1160s . Modern historians agree that John was born after 1168 , probably during the 1170s . 
 John was the youngest of the four sons of Erard II , Count of Brienne , and Agnes of Montfaucon . He seemed " exceedingly old ... about 80 " to the 14 @-@ year @-@ old George Akropolites in 1231 ; if Akropolites <a href='null_genetive' title='1'><mark>'</mark></a>estimate was correct , John was born around 1150 . However , no other 13th @-@ century authors described John as an old man . His father referred to John <a href='null_genetive' title='2'><mark>'s</mark></a>brothers as " children " in 1177 and mentioned the tutor of John <a href='null_genetive' title='3'><mark>'s</mark></a>oldest brother , Walter III , in 1184 ; this <a href='uninflect' title='4'><mark>suggests</mark></a> that John <a href='null_genetive' title='5'><mark>'s</mark></a>brothers <a href='uninflect' title='6'><mark>were</mark></a> born in the late 1160s . Modern historians agree that John was born after 1168 , probably during the 1170s . 
John was da youngest of tda4 sons of Erard II , Count of Brienne , and Agnes of Montfaucon . He seemed " exceedingly old ... about 80 " to the 14 @-@ year @-@ old George Akropolites in 1231 ; if Akropolites  estimate was correct , John was born around 1150 . However , no other 13th @-@ century authors described John as an old man . His father referred to John  brothers as " children " in 1177 and mentioned thdautor of John  oldest homeboy , Walter III , in 1184 ; dis suggest dat John  brothers was born in the late 1160s . Modern historians agree that John was born after 1168 , probably durin theda70s .