The Last Roman - An Alternate History Adventure Novel by Edward Crichton

http://www.amazon.com/dp/B00AGDONCC

People enjoy and connect with time travel stories because of its inherent fish out of water element.  The idea of a fellow human plopped into a fantastical world with no idea what to expect or how to react resonates with our sense of adventure.  It's because of this urge to explore and seek out new ideas and locations that Columbus sailed the ocean blue and Armstrong rocketed to the moon, but some of us don't have a choice in the matter.  As is the case for Navy SEAL Jacob Hunter, who finds himself trapped in Ancient Rome during the Age of Caligula after activating a mysterious and powerful artifact while on a mission in modern day Syria.

Hunter, a man familiar with history and too many cheesy Sci-Fi movies, must brave this much forgotten world and work with its duplicitous residents while simultaneously avoiding the ever present risk of changing history.  He's seen the movies and read the books and knows enough about Rome to have already realized that within minutes of their arrival, something has gone seriously wrong with the timeline.  History is not as he remembers.  Upon meeting the emperor Caligula, he finds the man to be completely different than how history remembers him.  The man is completely sane, and others in his family are not as he remembers either, but Hunter and his team must work with these people carefully as they try to stay alive and find their way home.  

He only hopes that he isn't around when Caligula finally fulfills his historical duties and turns into the insane tyrant who once proclaimed himself a god and vowed to appoint his horse as Rome's head of state...