In England, judges have devised a number of rules as to how to deal with precedent decisions. The early development of case-law in the thirteenth century has been traced to Bracton's "On the Laws and Customs of England" and led to the yearly compilations of court cases known as Year Books, of which the first extant was published in 1268, the same year that Bracton died. The Year Books are known as the law reports of medieval England, and are a principal source for knowledge of the developing legal doctrines, concepts, and methods in the period from the 13th to the 16th centuries, when the common law developed into recognizable form.