Wilhelm VI De Hornes
Wilhelm VI De was born about 1328.  He died in 1358.

 Mechtild Van Arkel
Mechtild Van was born about 1330.  She died after 1375.

 Wilhelm VII De Hornes
Wilhelm VII De was born before 1359.  He died  due to Killed in battle. on October 25th, 1415 in Azincort, France.