Imperiatrix

From TARDIS Index File, the free Doctor Who reference.

The Imperiatrix was a title held by the first female ruler of the Time Lords, a woman known as Pandora. (BFG: Imperiatrix, Lies)

In one possibe reality caused by the influx of Anti-Time, Romana held the position of Imperiatrix of the empire of Zagreus. (BFA: Neverland)