Mary Blennerhassett (died 1873) (d. 1873) Parents William Blennerhassett Catherine Johnson Children John Sinclair Bremer de Courcy William Blennerhassett de Courcy Sir Michael de Courcy Nevinson Willoughby de Courcy Siblings Arthur Blennerhassett John Blennerhassett Partners Nevinson Blennerhassett de Courcy