Katarina (Adrienne Hill)
Katarina was handmaiden to the prophetess Cassandra when the Doctor and Steven Taylor visited the besieged city of Troy, in 1184 BC.
When Steven was wounded, in a skirmish with a Trojan warrior, Katarina helped carry him inside the TARDIS, which took off with her still aboard. After leaving Troy they embarked on an epic adventure fighting the Daleks, during which the travellers were forced to land on a penal planet in a ship belonging to the Guardian of the Solar System, Mavic Chen.
They managed to escape, but a homicidal prisoner took Katarina hostage, and she opened the airlock's outer door, sacrificing herself to save the lives of Steven and the Doctor.