As I said in the other thread (think this is a more appropriate thread to give feedback) I made a little paint over of the king and four sons.
Great work on the shading and design!
I'm definately not an expert so just see it as my opinion.
I think the picture looks like it's trying to sell the chair the king is sitting on rather than the king and his sons. Try and focus the saturation on parts you wan't the viewer too look at.
I also changed the colours into a double complementary harmony (blue,orange,green,red). I believe that clothes with more saturation often is painted like that in classical paintings to make them look expensive. Fabric with a lot of saturation was rare in that era, wich I belive is why alot of painters liked to show that off in their images.