Carla (The Ravelli Conspiracy)

 was a friend of Niccolo Machiavelli and rescued Steven Taylor from a cell. She asked Steven to help her murder Guiliano de Medici. When Steven tried to escape she decided to poison everyone at the banquet. She was concerned when her plan failed. She was in love with Machiavelli. She helped Vicki Pallister to retrieve the TARDIS key from the Pope. She later trapped Vicki in the cell with the First Doctor and Steven. (AUDIO: The Ravelli Conspiracy)