The Son of Heaven — Philip Boast

The second Septimus Quistus mystery - AD64: Liu Zhang, the Son of Heaven, born to be Emperor of the mighty China, needs disgraced ex-senator Septimus Quistuss help to return to China in secret to claim his birthright. But a rebel Hun army stands in his way, and only Quistus is trusted by both the child and Nero, desperate to reopen the Spice Road, to escort him. And only Quistus could unmask a murdereralong the way...