when did the doctrine of precedent begin to emerge in english common law
Common law The doctrine of precedent developed during the 12th and 13th centuries,[73] as the collective judicial decisions that were based in tradition, custom and precedent.[74]
Law of the United States At both the federal and state levels, with the exception of the state of Louisiana, the law of the United States is largely derived from the common law system of English law, which was in force at the time of the American Revolutionary War.[14][15] However, American law has diverged greatly from its English ancestor both in terms of substance and procedure,[16] and has incorporated a number of civil law innovations.