Pope Pius XII (Eugenio Pacelli)
He'd be canonized by now if he had smiled more.
But, I suppose having been involved with World War I, the redrawing of the boundaries of Europe, Mussolini, the Weimar Republic, Nazism, Communism, the Great Depression, World War II, the Holocaust and the Cold War, he didn't have a lot to smile about.
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From an article in the NY Times in 2001