In the summer of 1516, Michelangelo worked out a third
contract for the tomb of Julius and then returned to Florence,
which was now ruled by the Duke of Urbino, who was in turn replaced
by Giulio de' Medici. Michelangelo also took on a protégé, the
painter Sebastiano del Piombo. The reigning Pope, Leo X, offered
Michelangelo numerous commissions to improve Florence, all of which revolved
around the considerable additions being made to San Lorenzo, the
Medici family's parish church. Planning for the additions to San
Lorenzo began in 1517 with models for a new facade for the church,
which was Michelangelo's first serious architectural undertaking.
Concurrently with the design for the San Lorenzo facade, Michelangelo
worked on a Statue of Christ and continued working
on the tomb of Julius in Rome and in Florence. He even began the
monumental task of removing marble from the quarry for the San Lorenzo
project, and was outraged when the contract was canceled in 1520.
By 1520, Michelangelo was the unquestioned master of Italian art,
since both of his primary rivals, Leonardo and Raphael, were both
dead. He continued with his poetic efforts, and made his first
mention of his homosexual longings. Pope Leo X suddenly died in
1521.
In 1521, while the Reformation gained momentum, Michelangelo
began working on the Medici Chapel and on the Biblioteca Laurenziana projects.
He also continued his series of unfinished Slaves, which
were never used for the tomb of Julius, but which remain as important
testaments to the sculptor's working process. The Chapel project
was an architectural and sculptural fusion of Christian and Classical
motifs that entailed the construction of tombs for two Medici dukes.
As part of the Chapel, Michelangelo worked on the Allegories
of the Phases of the Day, four nudes representing Dawn,
Day, Evening, and Night, until 1534. Even then, the Chapel was
incomplete, and the position of the nudes on the sarcophagi is
most likely not their originally intended position. However, they
are among Michelangelo's finest nudes and are excellent examples
of his combining action with repose. Day and Evening are male figures,
the former robust and young, the latter aging and limp; Dawn and
Night, although female, are obviously based on male models, who
represented for Michelangelo the superior human form. Meanwhile,
in 1523 Leo X was succeeded by Giulio de'Medici, Leo's cousin and
another of Michelangelo's childhood friends, who became Pope Clement
VII. In 1525 Michelangelo signed another contract for the tomb
of Julius, which had, at this point, been drastically scaled down.
Michelangelo worked simultaneously on the tomb, the Chapel, and
the biblioteca until 1527, when Spanish and German
mercenaries hired by Holy
Roman Emperor Charles V invaded, sacked, and devastated Rome.
Famine and plague followed the violence. The Florentines drove
the Medicis out of Florence once again, and proclaimed a second
Florentine Republic. In 1529, Charles V and Clement VII made a peace
agreement that stipulated that the Medicis should return to power
once more. The Florentines decided to protect themselves from the
allied forces of the Pope and the Holy Roman Empire, and hired
Michelangelo to design new fortifications for the city. This project
occupied him for much of 1528 and 1529. In the midst of the military
project, Michelangelo visited Ferrara to do some painting and ask
military advice of the Duke there. He returned to Florence in September,
but promptly fled to Ferrara and then to Venice to avoid the imminent
invasion. Michelangelo returned, however, after the Florentines
accused him of treason, and was in Florence when Charles V's troops
took the city and restored power to Clement VII. Michelangelo,
accused of treason by both the Florentines and the Roman Pope,
went into hiding. When Clement the VII offered him immunity if he
would work on the Medici Chapel, Michelangelo emerged and resumed
work on San Lorenzo, overseeing its construction until August 1532.