G. A. Henty 
Saint Bartholomew’s Eve / A Tale of the Huguenot Wars 

The hero, Philip Fletcher, is a right true English lad, but he has a French connection on his mother’s side. This kinship induces him to cross the Channel in order to take a share in that splendid struggle for freedom known as the Huguenot wars. Naturally he sides with the Protestants, distinguishes himself in various battles, and receives rapid promotion for the zeal and daring with which he carries out several secret missions.(Excerpt from Goodreads)