Try Katherine Roberts 'Seven Ancient Wonders' Books,they are set in ancient times,not in rome unfortunatly,but mostly in ancient cities and the like,tehya re based around the seven ancient wonders of the wood,they all have different protagonists and i think two of them have a 30 year time period difference,they go like this(it doesnt matter which order you read them,i actually read the 6th one first and the 1st one 6th,.....)
The Great Pyramid Robbery-The Great Pyramids Of Egypt-Narrated By Senu
The Babylon Game-The Hanging Gardens of Babylon-Narrated by Tiamat
The Amazon Temple Quest-The Temple of Ephesos-Narrated by ????(forgotten)
The Mausoleum Murder-????(forgotten)-Narrated by Alexis
The Olympic Conspiracy-The Statue of Zeus-Narrated by Sosi
The Collosus Crisis-The Collosus of Rhodes-Narrated by Aura
The Cleopatra Curse-????-????(havnt read yet)
great books set in historical times,some fo the books suit certain tastes more then others