The Julian Inscription

In the 3rd century AD, a Roman emperor has a chest buried in one of the ancient hills of Rome. But in the year 1939, when the Pope dies and is buried, the chest comes to light again and falls into the hands of none other than Hitler. And then it turns out that the chest contains one of the greatest secrets of Christianity.
More than sixty years later, American writer Don Huff is brutally murdered, shortly before he manages to fathom the meaning of the mysterious contents of the chest. And to solve her father's murder, his daughter calls on an old friend, Langdon Reilly, for help.
The trail Langdon follows takes him on a race across Europe, bringing him ever closer to the secret that has been hidden since the days of the early Christians…