To what extent was the Renaissance in Europe the product of individual creative geniuses?

Renaissance is the name of the great intellectual and cultural movement of the revival of interest in classical culture that occurred in the fourteenth, fifteenth and sixteenth centuries -- a period that saw the transition from the Middle Ages to modern times. The influence of Greek and Latin culture that occurred as a result of the formation of extensive Latin cultures in the Eastern Mediterranean after the 4th Crusade can be regarded as the basic condition, if not directly the cause, of the Renaissance.

Italian life in the 14th and 15th centuries was lived among the vast ruins of the ancient Roman Empire. The cruelty and barbarism of Rome had long been forgotten and the splendour of that lost civilisation’s ruins suggested a glorious, golden past. By contrast, the period following the fall of Rome in the 5th century seemed to some Italian intellectuals and artists to be a period of decline and decay.

So, the Renaissance began in Italy, and its first period was marked by a ...