Marmaduke 1st Baron de Thweng , of Kilton
Marmaduke 1st Baron de was born in September 1256 in Kilton Castle, Cleveland, Yorkshire, England.  He died at the age of 66 on September 28th, 1322.

 Isabel de Ros
Isabel de was born about 1276 in Ingmanthorpe, Kirk Deighton, Yorkshire, England.  She died before December 31st, 1318 in Kilton Castle, Cleveland, Yorkshire, England.

 Alice de Thweng
Alice de was born about 1290 in Kilton Castle, Cleveland, Yorkshire, England.

 Lucy de Thweng
Lucy de was born about 1295 in Kilton Castle, Cleveland, Yorkshire, England.  She died before 1325.

 Katherine de Thweng
Katherine de was born about 1318 in Kilton Castle, Cleveland, Yorkshire, England.  She died before May 28th, 1374.