There is always a danger in success. It begins with talent, continues with training and experience, blooms with surprising genius, flowers into widespread acclaim, culminates in fame and fortune, and then, all too often deteriorates into formulaic monotony. It's the broken record story of all too many very famous artists. Part of it can be attributed simply to the nature of the human life cycle from explosive youth to the decrepitude of old age. Yet a few artists manage to avoid it--Claude Monet for one, also Winslow Homer, Matisse, Cezanne, Rembrandt, and Salvadore Dali--just to name a few; artists whose last works were as fresh and expressive as the work from any other portion of their lives.
Yet the list of those who succumbed to what I would call the loss of spirit in their work is just as illustrious. No less an art icon than Leonardo da Vinci suffered this fate. Many of his works were exceptional only in their conception, not in their execution. His declining years were spent as a royal pet of the French King Francis I. Picasso coasted through the last quarter century of his life on the styles, symbols, and trademark images he'd made popular in his prime. And another interesting study in this phenomena was the Early Renaissance artist Pietro Perugino.
Born in 1445 in Italy near Perugia (from whence he got his nickname), his real name was Pietro di Cristofor Vannuci. He was fortunate from birth, acquiring a background in art from the Umbrian school, then moving to Florence, the hotbed of artistic flower, at a time when artists such as Leonardo, Verrocchio, della Francesco, and Ghirlandaio were either teaching or learning their craft. It was the Medici era. Lorenzo the Magnificent held court, teaching and sheltering artist and intellectuals of all stripes. Though none of his early works survive, Perugino's reputation for a time even outshone that of his colleague, Leonardo. He was called to Rome to work with Ghirlandaio, Botticelli, and Cosimo Roselli in decorating the newly completed Sistine Chapel. His Delivery of the Keys to St. Peter is probably his earliest existent work.
Returning to Florence and Perugia, he was very much in demand for his religious works and portraits. It was at this time he took on his best and brightest student, Raphael Sanzio. At this apogee of his career, his spectacular, if somewhat sentimental, altarpieces brought him vast fame and fortune. He was not a religious man, however. Vasari writes that he would do anything for money, which seems to have been the case in that many of his commissions during the last years of his life were formulaic wall decorations which gradually became more and more old fashioned in appearance. After 1500 until his death in 1525, there is a tired sameness, a sort of lifeless, uninspiring calligraphy to his figures which today, unfortunately, makes up the bulk of his existing work. Perugino even suffered the ignominious fate of having some of his deteriorating frescos torn from the walls of his beloved Sistine Chapel within just a few years after his death. They were replaced by Michelangelo's Last Judgment.