For nearly four years the sculptor remained among the mountains of Carrara, and the adjacent ones of Serravezza, taking out heavy blocks of marble, making roads over the steep rocks for their transportation, and studying architecture with great assiduity. Meantime, Michael Angelo writes to his "Dearest father: Take care of your health, and see whether you are not still able to get your daily bread; and, with God's help, get through, poor but honest. I do not do otherwise; I live shabbily, and care not for outward honor; a thousand cares and works burden me; and thus I have now gone on for fifteen years without having a happy, quiet hour. And I have done all for the sake of supporting you, which you have never acknowledged or believed. God forgive us all! I am ready to go on working as long as I can, and as long as my powers hold out." Later he hears that his father is ill, and writes anxiously to his brother, "Take care, also, that nothing is lacking in his nursing; for I have exerted myself for him alone, in order that to the last he might have a life free of care. Your wife, too, must take care of him, and attend to his necessities; and all of you, if necessary, must spare no expenses, even if it should cost us everything." Finally the façade of San Lorenzo was abandoned by Leo X., who decided to erect a new chapel north of the church, for the reception of monuments to his brother and nephew, Giuliano and Lorenzo. The artist built the new sacristy, bringing thither three hundred cart-loads of marble from Carrara. Leo died in 1521, and was succeeded by Adrian, who lived only a year, and then by Clement VII., the cousin of Leo X. He was a warm friend of Michael Angelo, and so desirous was he of keeping the artist in his service that he endeavored to have him take holy orders, but the offer was refused. Like the other popes he wished to immortalize his name, and therefore gave the artist the building of the Laurentian library, adjoining San Lorenzo. Meantime the relatives of Pope Julius were justly angry because his tomb was not completed, and threatened to imprison the sculptor for not fulfilling his contract. All art work was soon discontinued through the sacking of Rome by Charles V. of Germany, in 1527. Upon the inlaid marble floor of the Vatican the German soldiers lighted their fires, and with valuable documents made beds for their horses which stood in the Sistine Chapel. Rome had ninety thousand inhabitants under Leo X. A year after the conquest, she had scarcely a third of that number. The Florentines now expelled the Medici, revived the republic, and appointed Michael Angelo to superintend the fortifications and defences of Florence. He had always loved liberty. Now he loaned his funds freely to the republic, fortified the hill of San Miniato, was sent to Ferrara by the government to study its fortifications, and also on an embassy to Venice. He showed himself as skilful in engineering as in architecture or painting.