Diego Rivera was a Mexican painter and the husband of Frida Kahlo. (COMIC: The Way of All Flesh)
The document that came to be known the Rivera Manuscript was given to Rivera by a model or lover shortly before he left the United States in 1933. Still upset over the vandalisation of his Rockefeller mural, he did many rough sketches of the events of the Manuscript. Though he lost or sold the manuscript shortly after his arrival in Mexico, The Book of the War said the unfinished canvases "rivalled, or even surpassed, Picasso's Guernica in power and insight." (PROSE: The Book of the War)
The Tenth Doctor said he visited him and his wife a couple of times after an incident in 1941. (COMIC: Revolutions of Terror)