Strella

Princess Strella of Tara was taken prisoner by Count Grendel of Gracht.

He intended to use her to gain a place on the throne. She was identical in appearance to Romana I who, along with the Fourth Doctor, freed her. The android replica of Strella created by Grendel announced her full title as "Princess Strella, descendant of the Royal Kings of Tara, Mistress of the domains of Thorvald, Mortgarde and Freya". (TV: The Androids of Tara)

She later encountered the Seventh Doctor and Bernice Summerfield. (PROSE: The Trials of Tara)

Appearance
Strella was a young woman almost identical to Romana I, with differences so minute that none but the closest friend or relative would be able to tell the difference. Strella's hair was slightly darker, her nose a fraction longer and her forehead not so high. (PROSE: Doctor Who and the Androids of Tara)

Behind the scenes

 * Mary Tamm played Princess Strella in parts two and four, and an android duplicate of Strella in parts two and three, but was credited only as "Romana" both on-screen and in Radio Times.