The Vatican Palace or, according to its official name, the Apostolic Palace (also called the Sixte-V Palace, or formerly, the Sacred Palace) has been one of the residences of the Popes since their return from exile in Avignon (1377). 

Previously, and for more than a millennium, the popes lived in the Lateran Palace near their cathedral, the Archbasilica of Saint John in the Lateran. Since the entry of Italian troops into Rome on September 20, 1870, the sovereign pontiffs could no longer stay at the Quirinal Palace, which had become the residence of the kings of Italy, then that of the presidents of the Italian Republic.  The popes now live and work permanently in the apostolic palace, near the tomb of Saint Peter of which they are the successors.

The construction of the new palace did not begin until Nicholas V's pontificate in the fifteenth century. He wanted to make it the largest palace in the world. But he was only able to realize a small part of his plans.

The palace houses the Sovereign Pontiff's apartments (except for Pope Francis, currently reigning, who has chosen to live in the residence of Sainte-Marthe). The building is also the location for the Roman Curia offices, the Vatican Apostolic Library, and part of the Vatican Museums.

It is a complex of 55,000 m2 comprising approximately 1,400 rooms, making it the largest fully-inhabited palace in the world. The Vatican Museums included in the Apostolic Palace include the Sistine Chapel, the Nicoline Chapel, the Raphael Rooms, and the Borgia Apartments.