In 1853, Mary Todd Lincoln, the wife of Abraham Lincoln, gave birth to Thomas, named after his recently deceased paternal grandfather. Lincoln nicknamed his youngest son "tadpole", which was then abbreviated to "Tad." Hampered by a speech impediment, Tad was slow to learn to read and write, and he had trouble communicating with others, but his father could understand Tad perfectly and empathized with the boy's frustrations. Known for his affectionate and impulsive personality, Tad became the focus of Lincoln's attentions after the death of his second son, William Wallace in 1862. Tad died in 1871. Of Lincoln's four sons, only Robert, the eldest, lived to adulthood.
	Thomas "Tad" Lincoln 1853 - 1871
	Mathew Brady Studio Albumen silver print (carte de visite), 1865 8.7 x 5.4 cm (3 7/16 x 2 1/8 inches) National Portrait Gallery, Smithsonian Institution, Washington, D.C.