Talbot Mundy 
Tros of Samothrace [EPUB ebook] 

The cable that Julius Caesar has made in helping find the best way to attack Britain is to play a double game. He must save his father and encourage the resistance of the British leaders to remove Rome from its legions that are ready to conquer the land of Gaul. Offenses, intrigue, and many murders pose a threat to accompaniment by Caesar’s Caesar in his amphibian landings and battles.