In 1914, London had 16 murders from a population of 7.1 million. That's a homicide rate of .22 per 100,000. By comparison, Detroit had a murder rate of 46 in 2007. That's 209x the rate of Edwardian England. If New York reduced its homicide rate to that of Edwardian London, it would save the number of lives lost in September 11th every four years.
In 1914, London had 16 murders from a population of 7.1 million. That's a homicide rate of .22 per 100,000. By comparison, Detroit had a murder rate of 46 in 2007. That's 209x the rate of Edwardian England. If New York reduced its homicide rate to that of Edwardian London, it would save the number of lives lost in September 11th every four years.
Historical murder rates for all of England from 1900 are here: http://www.parliament.uk/commons/lib/research/rp99/rp99-111....
As for murder rates going further back, Gregory Clark has a chart of this in his book Farewell to Alms. See page 127: http://www.amazon.com/gp/reader/0691141282/ref=sib_dp_srch_p...!
The homicide rates seem to be around 20 per 100,000 for 1300, then about 5 per 100,000 for 1600, and then under 1 per 100,000 after 1800.
In other words, American cities have murder rates unseen since medieval times.