French painter Pierre Bonnard wouldn't be the painter everyone knows if it weren't for the enigmatic Marthe. Indeed, the man nicknamed the "Painter of Happiness" in his homeland portrayed his wife, a self-proclaimed aristocrat, in more than a third of his paintings. Devoted to Impressionism and abstraction, Bonnard founded the Nabis group with other artists in 1888. Later, Marthe sinks into madness.