Alternate Rome

An alternate Rome existed at many times, either created in alternate timelines or as natural parallel universes.

The Rani's Rome
The Roman Empire of an alternate 10 BC was created for the Rani on an alternate Earth, called Terra Nova by the entity known as Iam. In this alternate timeline, Rome generated electricity, built airships and steam-driven galleys, broadcast radio, and had many other disturbing anachronisms. The Rani also tried to manipulate the alternate Cleopatra VII's three children, but failed. (PROSE: State of Change)

Magog's Rome
In another alternate Rome, Magog and four other Malevilus were worshipped for having led Rome in conquest of the galaxy. They later provided the alternate Romans with the technology to invade other dimensions. The Fourth Doctor imprisoned Magog in an empty dimension and started a revolution that led to the destruction of the other four Malevilus with the help of the robot Vesuvius. He left this Galactic Roman Empire in the hands of Vesuvius. (COMIC: Doctor Who and the Iron Legion)

20th century Rome
Investigating why the multiverse was contracting, the Sixth Doctor became stuck on several worlds. One was a 20th century Earth where the Roman Empire never fell. This alternate universe diverged from the prime universe when Julia Caesar  became empress of the  Roman Empire  and had her life prolonged by an alien technology. The Roman Empire eventually owned sixty percent of Earth. (PROSE: Spiral Scratch)