Of one of Madrid's main tourist attractions. It was once a fortress, then the old Alcázar or citadel, and finally the Royal Palace. It is the official residence of His Majesty the King of Spain, although he does not actually live here. Apart from its role as a museum, it is only used for ceremonial purposes on state occasions such as diplomatic functions and official events. The origins of the palace date from the 9th century, when the Muslim kingdom of Toledo, wishing to defend itself against surprise attacks by the Christians, built a fortress which was later used by the kings and queens of Castile. In the 16th century a citadel was built on the same foundations. On Christmas Eve, 1734, it was reduced to ashes by a fire. Soon after Philip V ordered a new palace to be built on the same spot. Work on the building was carried out between 1738 and 1755. It was designed as a vaulted structure made of stone and brick, and no wood or flammable materials were used in its construction. Charles III of Spain was the first monarch who took up residence there, in 1764. CAMILA, OLIVIA, IONE AND LAURA