A friend has written it and I am about 60 pages in and it's very good, I am thoroughly drawn into the story and it is structured very well etc. etc. but trying to market/ promote something like this is outside of my area of knowledge.
All I can think of is to find historical fiction forums and find tactful ways to get people to go read some of it on wattpad but that seems like a slooooooooow boat to China. Maybe see if there are any facebook groups etc. all seems like tons of work for maybe one or two sales, if any.