William Wallace Lincoln

William Wallace "Willie" Lincoln (December 21, 1850 – February 20, 1862) was the third son of President Abraham Lincoln and Mary Todd Lincoln. He was named after Mary's brother-in-law Dr. William Wallace.
Biography.
Willie and his younger brother Tad were considered "notorious hellions" when they lived in Springfield. Their father's law partner William Herndon said they pulled books off their shelves while their father appeared oblivious.
When Abraham Lincoln took office as President of the United States, Willie and Tad moved into the White House. To give them playmates, Mary Todd Lincoln asked Julia Taft to bring her younger brothers, 14-year-old "Bud" (Horatio Nelson Taft Jr., 1847–1915) and 12-year-old "Holly" (Halsey Cook Taft, 1849–1897) to the White House.
Willie and Tad became ill in early 1862, possibly with typhoid fever. Tad was relatively lightly affected but Willie gradually weakened; his parents spent much time at his bedside. He died on February 20.
Both parents and Tad were deeply affected. Lincoln said, "My poor boy. He was too good for this earth. God has called him home. I know that he is much better off in heaven, but then we loved him so much. It is hard, hard to have him die!"; after the burial, he shut himself in a room and wept alone. Mary Lincoln remained in bed for three weeks and was unable to attend Willie's funeral or look after Tad.
Abraham Lincoln took solace in caring for and comforting Tad, who remained very ill and was grieving himself for his brother's death. Tad also lost the companionship of Bud and Holly, whom Mary refused to allow in the White House anymore, as they reminded her too much of Willie.
Willie was interred at Oak Hill Cemetery in Georgetown. After Abraham Lincoln's assassination in 1865, he was re-interred at Oak Ridge Cemetery in Springfield, Illinois, first in a temporary tomb and in 1871 in a state tomb alongside his father and his brother Eddie. Tad and Mary Todd Lincoln were also later placed in the crypt of the Lincoln Tomb.
In fiction.
The 2017 novel "Lincoln in the Bardo" by George Saunders takes place during and after Willie's death and depicts Abraham Lincoln's grief. The novel won the 2017 Man Booker Prize and was the "New York Times" bestseller the week of March 5, 2017.
See also "The Murder of Willie Lincoln" by Burt Solomon (Forge, 2017, ).
A fictional version of the death of Willie Lincoln is also depicted in the novel and its subsequent movie "Abraham Lincoln, Vampire Hunter".