Which author wrote the 'Gordianus the Finder' series?

Steven Saylor wrote the Roma Sub Rosa series, whose central detective is Gordianus the Finder.

The historical mysteries are set in the final decades of the Roman Republic, placing Gordianus amid the worlds of Sulla, Cicero, Julius Caesar, and Cleopatra. Rather than investigating modern police cases, he works as a private finder whose cases unfold through Roman politics, law, family conflict, slavery, religion, and violence.

The series began with Roman Blood in 1991. Saylor often builds individual plots around real Roman history and surviving classical sources; Roman Blood, for example, draws on Cicero’s speech In Defence of Sextus Roscius of Ameria. The books are commonly called the Gordianus the Finder series, although Roma Sub Rosa is the series title used for the wider sequence. Saylor also wrote the large-scale historical novels Roma, Empire, and Dominus, which are related to his interest in Rome but are not Gordianus mysteries.