As an avid reader of ancient history, historical fiction, and mystery novels, I was pleased to stumble upon the SPQR series, which combines all three. No historical fiction I have ever read brings Republican Rome to life better than SPQR. The mysteries through the first four books haven't been all that mystical, but the excitement moves the stories along quite well.
Decius Metellus the Younger is a minor Roman Senator who serves in a series of menial government jobs and finds murder, mayhem, and mystery everywhere he goes. Each of the first three books of the series has ended with Decius fleeing Rome to escape the homicidal fury of those he has angered.
This story is different in that it takes place during one of Decius' many enforced absences from Rome. He goes to Egypt with a diplomatic mission headed by his uncle, Metellus Creticus. The book reads somewhat like a 'Lonely Planet' guidebook as Decius explores the city of Alexandria, visiting the Jewish Quarter, the Palace of the Ptolemies, the Pharos lighthouse, the Library, and many other long forgotten landmarks including the Temple of the Muses.
Decius encounters murder in the Temple, and being offended that so vile a crime could occur in so holy a place, he sets out to solve the murder and avenge the Muses. He manages to get on the wrong side of almost everyone he comes in contact with, evades a number of attempts on his own life, and uncovers a plot to overthrow the Roman influence in Egypt. When he wakes up one morning with a hangover and a murdered courtesan in his bed, things really get complicated. Not only does he get himself arrested for murder, he has a very hard time explaining things to his fiance. Not surprisingly, the story ends with the murder solved, the plot foiled, and Decius leaving the city in a very undignified manner.