http://19thcenturyrealism.com/category/traveller-artists/
https://www.youtube.com/watch?v=ADncja4MFug

But by far his greatest adventure was an invitation from the Chinese government to portray some important mandarins. On arrival he was told the true reason : the empress of the enormous Chinese empire wanted to be portrayed by Vos. As Vos did his job he had to overcome some cultural difficulties. He was not supposed to talk to the empress and after two sessions the empress made clear that his painting was too realistic, she wanted Vos to paint her as if she was much younger. This resulted in the following offical portrait of the dowager empress cixi which still can be seen in the summer palace in Bejing.