When discussing the rise and fall of empires, it is well to...

When discussing the rise and fall of empires, it is well to mark closely their rate of growth, avoiding the temptation to telescope time and discover too early signs of greatness in a state which we know will one day be great, or to predict too early the collapse of an empire which we know will one day cease to be. The life-span of empires cannot be plotted by events, only by careful diagnosis and ausculation--and as in medicine there is always room for error.