Heart of Darkness Question

The narrator then begins to discuss the history of the British Empire along the Thames; the details don’t specifically matter. He ends it by saying “Hunters for gold or pursuers of fame, they all had gone out on that stream, bearing the sword, and often the torch, messengers of the might within the land, bears of a spark from the sacred fire.” Who is he discussing (basically, not specifically)? What 2 things did these people go forth with, and what do those items represent? Think about the last phrase – what’s the sacred fire?