Cardinals are princes of the Church appointed by the Pope.[49] He generally chooses bishops who head departments of the Roman Curia or important episcopal sees throughout the world. As a whole, the cardinals compose a College of Cardinals which advises the Pope, and those cardinals under the age of 80 at the death or resignation of a Pope elect his successor. Their heraldic achievement is surmounted by the red galero and tassels as a form of martyred position in the Church.