It was on All Saints' Day in 1512 that Pope Julius II chose to display Michelangelo's paintings on the ceiling of the Sistine Chapel for the first time.
It took Michelangelo four years to complete the paintings that decorate the ceiling of the chapel. The paintings are of scenes from the Old Testament, including the famous center section, "The Creation of Adam." The chapel itself was built about 25 years earlier, and various Renaissance painters were commissioned to paint frescos on the walls.
Michelangelo was 33 years old at the time, and he tried to point out to the pope that he was a sculptor, and not really a painter, but the pope wouldn't listen. Michelangelo used his skills as a sculptor to make the two-dimensional ceiling look like a series of three-dimensional scenes — a technique that was relatively new at the time.
It took him four years to finish the job, between 1508 and 1512. He worked from a scaffold 60 feet above the floor, and he covered about 10,000 square feet of surface. Every day, fresh plaster was laid over a part of the ceiling and Michelangelo had to finish painting before the plaster dried.
The German writer Wolfgang von Goethe wrote, "We cannot know what a human being can achieve until we have seen [the ceiling of the Sistine Chapel]."
Julius II was a big patron of the arts - his tomb is a valuable stop in your tour of Rome:
https://en.wikipedia.org/wiki/Art_patronage_of_Julius_II
And of course All Saints Day is already a really rich occasion that is further enlivened with important commemorations like the unveiling of the ceiling.
What are your favorite Sistine Chapel and / or All Saints Day memories from Italy?