As Jonathon Richman of the proto-punk band the Modern Lovers elegantly put it, “Pablo Picasso never got called an asshole” — although the genius’ girlfriend Fernande Olivier must have been sorely tempted in the late summer of 1908, when she learned that Picasso had invited half of Montmartre to their squalid garret and given the food caterer the wrong date. Actually, everything turned out for the best: The resulting “Rousseau Banquet” was a resounding success, an all-night extravaganza whose details have been lovingly told and retold for the last hundred years. Today, it is regarded as the symbolic highlight of the Parisian Belle Époque. The key to its success, historians agree, was its giddy spontaneity, a fact that provides an object lesson to many of today’s practicing hosts. As far as we can ascertain, even allowing for nostalgia and self-serving exaggeration in the guests’ memoirs, the event really was a… More…