The focal point of the magazine's efforts in this respect came with the rise of Marcus Garvey, the gifted Jamaican leader whose "Back-to-Africa" movement, as it was popularly called, was founded on the premise, according to Du Bois, that " a black skin was in itself a sort of patent to nobility".
I thought that the main sentence of this sentence is "the focal point came with the rise". But one video I saw told me that the verb of the main sentence was "was founded". What exactly is the main sentence here? Could you please answer me? Here comes another question. What exactly does the phrase "according to Du Bois" describe? In my opinion, it describes probably the opinion that "Back-to-Africa" was founded on the premise that blabla..., however, the google translator tells me that it describes the opinion that the focal point came with the rise of .....(the whole sentence).
I'm so sorry for my poor expression. Could anybody help me? Thank you so much.