When?
When I went to England last month on a legal junket, one Oxford professor noted that the reason English courts were allowed to create published precedents, which were then followed, and became law as it were, was that it was all in "legal French," until the late 18th century, not understood by Parliament, and by the time the action was writen in English, it was too late for Parliament to recoup its lost power, in that regard. The tradition of courts creating legal precedents, with the force of law. had become too ingrained, to reverse. Tradition, tradition! In Civil Law countries, although it is changing now in many Civil Law nations, courts are not allowed to create legal precedent with the force of law, in the sense that subsequent courts must follow such prececents, if lower courts.