Margaret's brother, James, was a canon at Cassels in Flanders, who also served as chaplain to the French Ambassador at Rome.

James owned property near Avignon and helped pay for the education of his sister's many children.

[1] He was author of the following privately printed work: Statuta Synodalia pro unitis Diœcesibus Cassel.

lecta, approbata, edita, et promulgata in Synodo Diœcesana; cui interfuit clerus utriusque Diœoeceseos, habita prima hebdomada mensis Septembris, anno M.DCCC.X., 2 vols., Dublin, 1813.

[4] This book contains a papal bull against freemasonry; a decree of the Council of Trent against duels, with an explanation of it in English to be given by each priest to his flock; and short memoirs of the archbishops of Cashel and the bishops of Emly.