Plato's "posthumous life" has undergone many changes during the twentythree centuries since Plato's physical death. Its flame shone brighter here, fainter there, it was kept glowing here with greater, there with lesser effort from those who knew more or less of its significance, but it never died out entirely. Platonism has been continuously, in all times and in all changes of political and social conditions, an effective factor in the culture of the European nations, and not only in philosophy, but also in science, religion and arts. Each era borrowed from it principally what it needed most, one appreciated more its positive doctrine, another its criticism and Socratic skepsis. There were thinkers who were not conscious of its influence, and others who disliked it, but they too contributed to keeping it alive. For some of them Plato remained the object of their interest and respect as a philosopher of the remote past, to be discussed and written upon primarily for his historical interest, but there were others who felt his living presence and considered it indispensable to argue with him, to learn from him and to contend with him: it was in them that Plato's posthumous life was most vigorous.