The sarcophagi, used as burial places by Roger II, Constance of Hauteville, Henry VI and Frederick II, were carved using elements of red porphyry, a symbol of royalty and power. Used by the Egyptians and during the Ptolemaic dynasty, after the conquest of Egypt by Augustus, porphyry also became a prerogative of the emperor in Rome. Difficult to work with due to its durability, porphyry continued to be used in the Middle Ages, where it embodied the colour of power.
