Khan Academy
Khan Academy: David, Oath of the Horatii
The "Oath of the Horatii" is typically presented as a prime example of Neoclassical history painting. View pictures and read about the techniques used by David in this essay.
New Advent
Catholic Encyclopedia: Nicolas Poussin
The Catholic Encyclopedia site gives you a rather extensive biography on Nicolas Poussin. Please note that ?The Catholic Encyclopedia? is a historic reference source and should be viewed in the context of resource material dated around...
Curated OER
Nicolas Poussin: Self Portrait at the Age of 55
Artcyclopedia gives you links to galleries and museums on the internet that have the work of Nicolas Poussin.