The Count St. Germain book is set in imperial Rome during and after the reign of Nero. I thought this would be an interesting book to read since it tells the origin of St. Germain's sometime companions Atta Olivia Clemens and Roger (here Rogerius), and the historical setting should be of interest.
I did enjoy the book, but I have to confess that it suffered from the usual Yarbro problem that the story arc is identical to every other book: Saint Germain is a wonderful person and citizen but his activities protecting abused members of society eventually cause him to come under suspicion and he's accused and sentenced to some sort of death, which he miraculously survives, followed by a hasty retreat to another locale. The difference between this book and others is that the climax really is a great scene with the count fighting in the Circus Maximus for his life and emerging trimphant. It's worth the buildup, even if it's improbable given what Yarbro has told us about the effect of sunlight and water on her vampires. It is markedly better that the ending of the last one I read, A Flame in Byzantium, where Olivia simply gets tossed into the Bosporus in a sack, and someone picks her up.
One of the better ones in the series, I would say.