The consequence of this has been unfortunate. Instead of going to the fountain-head for information, historians have for the most part contented themselves with relying on accounts supplied by writers on the one side or the other, sources which are always prejudiced and usually contradictory. To extract truth from the mutual opposition of two lies is an ingenious and useful task when evidence is not forthcoming at first hand; but it is a method less accurate than the examination of original authorities when these can be consulted. Nor is there only an obligation to devote attention to the trials themselves; they cannot be judged alone: and historians have not escaped error when, although they have studied the trials immediately within view from the actual reports, they have neglected to read them in the light of the preceding practice of the English courts of law, and to ground their opinions upon the whole judicial system which gave them their peculiar character, and of which they were an inseparable part. To appreciate properly the significance of the trials they must not be taken apart from their setting, and it is necessary before passing judgment upon the events recorded in them to review the past which lies behind them and the causes which influenced their nature. The judicial system of England in the latter half of the seventeenth century was very different from its descendant in the twentieth. Its nature had been determined by the course of political events which moulded it into a form as unlike to that of two centuries after as the later Stuart constitution was to the Victorian.