In the frame story that opens the novel, a sailor records what Marlow says as they sit on a boat on the Thames, the river that flows past London to the sea. Marlow muses about the Romans who first came up this river to conquer the Britons. In doing this, he is universalizing Kurtz's saga. What the modern northern Europeans, including the British, have done in Africa to the Africans is no different from what the Romans did to the northern Europeans almost two thousands years ago. The patterns of conquest and cruelty to those that are deemed the "other" have been going on forever, and what we do now is just a "flicker" in a larger pattern.
Marlow says, for example, that "this" place, Britain, has also been a heart of darkness, as Africa is in the time of the novel:
"And this also," said Marlow suddenly, "has been one of the dark places of the earth."
Marlow goes on to imagine what it was like for a Roman commander 1,900 years ago who might have felt surrounded by savagery:
I was thinking of...
(The entire section contains 3 answers and 839 words.)