The weakest spot in the attempt to define, describe, and understand the Renaissance is our failure to consider causes. This failure is largely due to a failure of definition in time. The beginning has been placed anywhere between the Sixteenth and the Fourteenth Centuries. Most of the causes which have been suggested (the fall of Constantinople, the invention of printing, the discovery of America) are Fifteenth Century phenomena. But it is generally agreed that humanism began with Petrarch. I think we must ask ourselves why the Latin classics, which had been lying about in neglected corners of libraries, should suddenly become the most valuable things in the world. It is not enough to attribute this new enthusiasm to “fashion.” Men turn eagerly to new ideas chiefly when they are dissatisfied with the old; and there were good reasons for dissatisfaction in Italy in Petrarch's day.