The Supreme Leader of Gallifrey and President of the Inner Council and the Outer Chambers of the Judiciary (AUDIO: Arbitration) governed the Inner Council of Regenerators on an alternative Gallifrey. Following the death of the Supreme Leader, the High Chancellor would succeed them.
President Romana was Supreme Leader until she was assassinated by Vansell. Before Chancellor Narvin could take her place, however, Romana II took on her counterpart's identity and claimed that a double had been killed in her place. (AUDIO: Forever)