word origin - Sheriff

Today's English counties were shires, which is why we have Lancashire and Nottinghamshire.  Over each shire was placed a Riff (rifleman) one of whom became the shire-riff of Nottingham.

Today we call them Sheriffs.

source, Word Origins: http://www.narniafans.com/forum/archive/index.php/t-29445.html

and from 

Robert Lacey and Danny Danziger's book "The Year 1000: What Life Was Like at the Turn of the First Millennium, An Englishman's World".

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