Mary Todd Lincoln Was Institutionalized After President's Death (AP) SPRINGFIELD, Ill. A historian has discovered letters written by Abraham Lincoln's wife during her stay at a sanitarium years after her husband's assassination. It was believed Mary Todd Lincoln's son had burned the letters to hide details of mother's mental health. But historian Jason Emerson came across photographed and handwritten copies of the letters in an attic last summer in Maryland. Eleven letters were from what have been called Mary Todd Lincoln's "insanity years." Emerson writes in the current issue of American Heritage magazine that the documents contain no major revelations....