Fanny and the regent of Siam

This is one of those novels that is based on truth, but rather like Anna and the King, it is sometimes difficult to know where the truth ends and the fiction starts. The book is about the life of Fanny Knox, a daughter of Thomas Knox, who was the British Consul-General to Siam during the days of Anna Leonowens. One of Fanny's suitors was Louis Leomowens, the son of Anna (who appears as a young boy in the Anna movies. Fanny rejected Louis, who ended up marrying her sister Carolyn Knox. The book tells of the problems caused Fanny also rejecting the advances of a person well connected in Thai society.