From The Art and Popular Culture Encyclopedia
The palace is a complex of buildings, comprising the Papal Apartments, some of the Catholic Church's government offices, a handful of chapels, the Vatican Museums and the Vatican Library. In all, there are over 1,000 rooms with the most famous including Raphael's Rooms and the Sistine Chapel with its renowned ceiling frescoes painted by Michelangelo (restored between 1980 and 1990).
The other papal residences are at the Lateran Palace, and the Castel Gandolfo outside Rome. The Vatican Palace displaced the Lateran Palace in prominence during the fifteenth century; but it was eclipsed for an extended period by the Quirinal Palace.
Before 1871, the Quirinal Palace was the Pope's official residence. After the final overthrow of the Papal States in 1870, the King of Italy confiscated that palace in 1871, making it the King's official residence. After the abolition of the Italian monarchy in 1946 it became the residence of the President of the Italian Republic.