The Central Staircases of the Nicchione
The curved central staircase of the Nicchione was constructed by Bramante under Julius II (1503-1513) and then integrated with the adjacent, semicircular corridors under Julius III (1550-1555). These corridors previously held the Etruscan collection, but now feature the Egyptian Collection. As affirmed by Vasari in 1568, the first staircase was rendered unusable during the incorporation of the Nicchione, so Michelangelo designed two sets of stairs made of Peperino stone. At the beginning of the seventeenth century, when the Vatican Basilica courtyard was demolished, the well-known bronze pinecone was placed under the Nicchione. One century later, Pope Clemens XI (1700-1721) built the current staircases, which are identical to the original design by Michelangelo.
Restorers will perform the bocciardatura (bushing). The bushing is a surface machining of stone-to-beam elements that creates a slightly corrugated surface dusting the dirt off.