Walter Schiedel and Steven Friesen, two historians of the Roman Empire, have recently attempted to estimate wealth inequality in the Roman Empire when it was at its zenith using papyri ledgers, previous scholarly estimates, imperial edicts, and Biblical passages. Schiedel and Friesen estimate that in 150 AD, the top 1% of Roman society controlled 16% of the wealth, less than half of what America’s top 1% control today! It is also much lower than wealth concentration in N. Ireland - according to the estimate in my recent OEP article, the top 1% of population back in 2001 controlled 22% of the wealth. I have no doubt that that figure is much higher for 2011. You can read more about Schiedel and Friesen's work here.
My colleague and former PhD student Gareth Campbell has created a website about the British Railway Mania - click here . This episode has been described by the Economist as probably the greatest bubble in human history. Gareth's website provides background on the Mania and posits some explanations for the 'bubble'. In his explanation of why the bubble happened, Gareth places a lot of emphasis on investor myopia regarding future dividends and uncalled capital. His study of investors during the episode does not support the view that this episode was fuelled by naive and irrational investors.