In the early 1950’s, historians who studied pre-industrial Europe (which we may define here as Europe in the period from roughly 1300 to 1800) began, for the first time in large numbers,to investigate more of the pre-industrial European population than the 2 or 3 percent who comprised the political and social elite: the kings, generals, judges, nobles, bishops, and local magnates who had hitherto usually filled history books. ……One way out of this dilemma was to run to the records of legal courts, for here the voices of the non-elite can most often be heard, as witnesses, plaintiffs, and defendants. These documents have acted as “a point of entry into the mental world of the poor.” Historians such as Le Roy Ladurie have used the documents to extract case histories, which have illuminated the attitudes of different social group (these attitudes include,but are not confined to, attitudes toward crime and the law) and have revealed how the authorities administered justice. ……The extraction of case histories is not, however, the only use to which court records may be put. Historians who study pre-industrial Europe have used the records to establish a series or categories of crime and to quantify indictments that were issued over a given number of years. ……问题：The author suggests that, before the early 1950’s, most historians who studied pre-industrial Europe did which of the following?