"From the top of the campanile, or Giotto's bell tower, in Florence, one can look out over the city in all directions, past the stone banking houses where the rich Medici lived, past the art galleries they patronized, past the magnificent cathedral and churches their money helped to build, and on to the Tuscan vineyards where the contadino works the soil as hard and efficiently as he probably ever did. The city below is busy with life. The university halls, the shops, the restaurants are crowded. The sound of Vespas, the "wasps" of the machine age, fills the air, but Florence is not today what it once was, the center in the 15th century of a great civilization, one of the most extraordinary the world has ever known. Why? ­­What produced the Renaissance in Italy, of which Florence was the center? How did it happen that such a small population base could produce, in the short span of a few generations, great historical figures first in commerce and literature, then in architecture, sculpture and painting, and finally in science and music? Why subsequently did Northern Italy decline in importance both commercially and artistically until at the present time it is not particularly distinguished as compared with many other regions of the world? Certainly the people appear to be working as hard and energetically as ever. Was it just luck or a peculiar combination of circumstances? Historians have been fascinated by such questions ever since they began writing history, because the rise and fall of Florence or the whole of Northern Italy is by no means an isolated phenomenon."