Burchard de Avesnes
Burchard was born in 1182.  He died at the age of 62 in 1244.

 Margaret I de Flanders Cts de Flanders
Margaret I de Flanders was born on June 2nd, 1202.

 Jean de Avesnes Ct de Flanders
Jean de Avesnes was born in 1218 in Etroeungt, Nord, France.  He died at the age of 39 on December 24th, 1257 in Valenciennes, Nord, France.