Androzani Major was the twin planet of Androzani Minor in the Sirius System. It was the home of the Sirius Conglomerate that was incredibly wealthy and had tremendous influence.
It was colonised by Earth and the Doctor visited the planet during its early days. Centuries later, it possessed a federal government, with a ruling body called the Praesidium headed by a president and an army called the "federal forces". The Conglomerate's chairman, Morgus, had great influence over the Presidium and was influential enough for the army's commanding officer on Minor to pass information on to him before the President. Spectrox, a chemical that could slow down ageing, was a major commodity and was harvested by androids.