"at the sign of The George, by the steps of the Upper Moor Fields"

 Moorfields lies within the City of London, near Moorgate.  In Roman times, an 18 foot wall was erected around the area we still refer to as the 'Square Mile', which at the time was the whole of London.  Moorfields was one of the only open spaces within this area.  Divided into three, Upper Moorfields technically lay outside of the boundary.  Many people settled there after the Great Fire of London in 1666 forced people out of their homes.  The area was not salubrious, and became notorious for its molly houses in the 18th Century, along with the usual brothels, highwaymen and thieves.