The man who performed the first open heart surgery was African American with light skin colour. So to those who say that the casting of Frank Dillane was inaccurate, they should think twice before judging the production of Essex Serpent. Please look at the pictures of Daniel Hale Williams, he was a son of an Irish and African and the actor cast for the role Frank, he is a son of an English and Afro-Jamaican , so it is not because his skin colour is light that he is not mixed race or African descent. He is the perfect example of the perfect casting. People need to stop being obsessed with colours and investigate how accurate things are before spreading hateful comments.