On this day (Feb. 20) in 1862, President Abraham and Mary Todd Lincoln’s 11-year-old son, William Wallace “Willie” Lincoln, died after a two-week battle with what appeared to have been typhoid fever.

His illness probably was caused by the drinking of contaminated water from a polluted canal just south of the White House. In mid-January, both Willie and his younger brother Thomas “Tad” (1853-1871) contracted the disease, but happily the younger boy recovered a few weeks after Willie’s death.

Although both parents, but especially the father, doted sometimes excessively over all of their sons, Willie seemed to have been a particular favorite of his dad, who spent many hours playing with his “sweet-tempered and gentle-mannered” third son.