In November 1518, Michelangelo send this letter to cardinal Giulio de’ Medici (the future Pope clemente VII), appointed manager of the San Lorenzo’s factory by his cousin Leone X, in which he reassured him about the progress of the work to get the marble for the realisation of the San Lorenzo’s facade. The assignment , long awaited from Michelangelo, remained as we know unfulfilled. The letter shows the fervent activity as architect taken by Michelangelo between 1516 and 1534, year of his final departure to Rome.