War and Peace chronicles the history of the French invasion of Russia and the impact of the Napoleonic era on Tsarist society through the stories of five Russian aristocratic families. Tolstoy said War and Peace is "not a novel, even less is it a poem, and still less a historical chronicle". Large sections, especially the later chapters, are a philosophical discussion rather than narrative. Tolstoy also said that the best Russian literature does not conform to standards and hence hesitated to call War and Peace a novel. Instead, he regarded Anna Karenina as his first true novel. According to the Encyclopedia Britannica, "no single English novel attains the universality of Leo Tolstoy's War and Peace.