Most of these cases are from the records of the Eyre Court of Oxfordshire in 1241. There was an Eyre Court in each county, taken by one of the king's judges, who travelled to the county regularly. A jury of twelve men from each of the "hundreds" (districts of the county) of Oxfordshire brought any case or legal problem to the Eyre Court which could not be dealt with by local courts. The modern equivalent is the Crown Court.
In comparison to modern court cases, the cases were heard quickly. The judge listened to each side, asked a few questions and gave his decision. Even if he asked the jury for their verdict, they did not retire, but talked it over for a few minutes in the courtroom and announced their verdict. Cases rarely lasted more than half an hour. A mix of very different types of cases was heard, one after another. (See also Case-Study 2 for some of the other cases the judge tried in Oxford that year.)
Source 6 is from the royal records. The crime described is on a different scale from the others. The de Folvilles terrorised parts of Leicestershire with a large gang of followers throughout the 1320s and 1330s. Clearly neither the king, nor anyone else, was able to stop them.

To decide whether the amount of violent crime is great or small, the number of murders is measured against the number of people. Thus the number of murders per 100,000 people in 1995-7 was:
For London 2.1
For Washington D.C 69.3
For Moscow 18.1
And one historian's estimate for 14th century England: 12.0