Michelangelo
The novel you are referring to is likely "The Agony and the Ecstasy" by Irving Stone, which is a biographical novel about the life of Michelangelo. In the book, Michelangelo is the main character who interacts with Pope Julius II, but he does not become pope himself.
The cast of The Agony and the Ecstasy - 1965 includes: Harry Andrews as Bramante Maxine Audley as Woman Rex Harrison as Pope Julius II Charlton Heston as Michelangelo Alberto Lupo as Duke of Urbino Paolo Magalotti as Papal Guard Alec McCowen Furio Meniconi as Peasant Tomas Milian as Raphael Adolfo Pezzini as Man at Quarry John Stacy as Sangallo Fausto Tozzi as Foreman Venantino Venantini as Paris De Grassis
Michelangelo
Perhaps Michelangelo thought so at times. Somewhat unsure of his abilities as a painter, he is reported to have suspected the commission was a plot by the Papal architect Bramante to embarrass him with failure. He complained to Pope Julius II 'The place is wrong and no painter I'. The Pope often visited Michelangelo while he was working on the ceiling, and as the Pope often did he asked when Michelangelo would be finished. His answer was 'when I can' . One day the Pope was especially irritable and struck Michelangelo with his staff repeating 'when I can, when I can'. The Pope sent 500 ducats to Michelangelo as an apology and work continued.
It was the other way around. Michelangelo had to be persuaded and convinced to paint the ceiling of the Sistine Chapel. Michelangelo didn't like to paint and didn't considered himself a painter, he thought of himself as an sculptor. He agreed to paint the ceiling of the Sistine Chapel because you just couldn't say no to the Pope. During the Renaissance times, the Pope was the most important and powerful person in the world.
Pope Leo X favored the painter Raphael, who was renowned for his mastery and grace in art. Leo X appreciated Raphael's work, commissioning several pieces, including the famous "St. Peter's Basilica" frescoes. Raphael's ability to blend classical themes with Christian subjects resonated with the Renaissance ideals that Leo X championed.
Pope Paul VI was elected pope after the death of Pope John XXIII.
John Paul II
There is no pope named Pope XXIII. If you are referring to Pope John XXIII, he became pope in 1958.
Pope Francis is the reigning pope in 2013.
The current pope is Pope Benedict XVI.
Pope Pius III was the predecessor of Pope Julius II.