Lev Lvovich Sedov was the first son of the Soviet communist leader Leon Trotsky and his second wife Natalia Sedova. He was born when his father was in prison facing life imprisonment for having participated in the Revolution of 1905.

Lev Davidovich Bronstein, better known as Leon Trotsky, was a Russian revolutionary, Soviet politician, journalist, and political theorist. He was a central figure in the 1905 Revolution, October Revolution, Russian Civil War, and the establishment of the Soviet Union. Alongside Vladimir Lenin, Trotsky was widely considered the most prominent Soviet figure and was de facto second-in-command during the early years of the Russian Soviet Republic. Ideologically a Marxist and a Leninist, his thought and writings inspired a school of Marxism known as Trotskyism.