The master was now unable, owing to his extreme old age, to personally superintend the building, so that he constructed a wooden model, still preserved at the Vatican, after which his assistants carried on the work. From the window of his house Michelangelo used to watch for hours together the huge cupola slowly rounding itself against the sky, and wondered, perhaps, in how many years after his death it would be finished. The evening of Michelangelo's long life was saddened by the loss of nearly all who were near and dear to him. His two remaining brothers (for Buonarroto had died of the plague in 1528) passed away in Florence, and the only representative of the family, besides the aged artist, was his nephew Leonardo, only son of his favourite brother, Buonarroto. Although a confirmed bachelor himself, Michelangelo prevailed upon his nephew to marry, and Leonardo became the head of the still existing branch of the Buonarroti family. Another terrible loss to Michelangelo was the death of his faithful servant Francesco Urbino, of whom he wrote to Vasari: "While Urbino living kept me alive, in dying he has taught me to die, not unwillingly, but rather with a desire for death. The better part of me has gone with him, and nothing is left to me now but endless sorrow." In spite of old age, illness and afflictions, Michelangelo's last years were perhaps the busiest of a life of uninterrupted work. To this period must be attributed the plan for the improvements upon the Capitol; the design for the church of San Giovanni del Fiorentini; the drawing for the monument to Giangiacomo de' Medici which Leone Leoni erected in the Milan Cathedral; the plans for the conversion of the Baths of Diocletian into the church of Santa Maria degli Angeli, and a number of other drawings and sketches for palaces, statues, monuments, which other artists carried out. He found time for all these things while actively superintending the construction of St. Peter's, and yet his restless spirit was not satisfied. In a beautiful sonnet, beginning with the words Giunto è gia' il corso della vita mia, he laments the loss of his former creative power, and says that he has already felt the pangs of one death, while another is fast approaching. Nothing could be more pathetic than the spectacle of this strong creative spirit, already imprisoned in the iron embrace of death, yet struggling, like a Laocoon, against inevitable dissolution. Although nearly ninety years of age, Michelangelo would still walk abroad in all weathers, taking no precaution whatever. On February 14th, 1564, a friend of the master, Tiberio Calcagni, met him in the street on foot. It was raining hard, and Calcagni affectionately upbraided the old man for going about in such weather: "Leave me alone," cried Michelangelo fiercely, "I am ill, and cannot find rest anywhere."