Who is Mary Ann Morrison Jackson from Gods and Generals and what is their importance?

Mary Anna Morrison Jackson was Stonewall Jackson's second wife. He called her his 'esposita'. At the start of the novel, Mary had recently given birth to her first child who died a month later. She gave birth to their child just after the Battle of Fredericksburg. The baby was healthy, and Mary brought the child to visit Jackson after he was shot at Chancellorsville.