I don't think the common law was entirely spontaneous, as the central   
government of the time was involved in the effort to have local  courts   
adopt a common set of rules.  
  
What existed before was considerable variation between local   
jurisdictions.  This was of course one of the reasons for the evolution of   
merchant law.  
  
Paul Seabright uses the example of a shirt.  
  
Malcolm Rutherford