Maurice Denis — French Artist born on December 29, 1870,

Maurice Denis was a French painter and writer, and a member of the Symbolist and Les Nabis movements. His theories contributed to the foundations of cubism, fauvism, and abstract art... (wikipedia)

Remember that a painting - before it is a battle horse, a nude model, or some anecdote - is essentially a flat surface covered with colours assembled in a certain order.
All artists are now free to express their own personality.
Art is when things appear rounded.
All that is necessary to paint well is to be sincere.