"Articles like the ones just cited [Article 158] are also valuable sources on Serbian social history. However, they must be used with caution. For a series of laws is not the same type of source as a visitor's description of a society. A law code does not describe how things actually functioned but only how they ought to have functioned. In some cases articles may have been based on customary laws; in such cases the articles' contents were probably generally observed or practiced and thus can be taken as evidence about actual practices and conditions. However, an article could also reflect an innovation, a reform the ruler was trying to bring about through legislation. In this case it would not have reflected existing customs and we must then ask, was the ruler successful in realizing his reform or did it remain a dead letter? Thus a law code may at times more accurately depict an ideal than reality. And since certain—perhaps many—articles in Dusan's code may have been attempts to legislate change, attempts which may or may not have been successful (and even if successful in one place, possibly not in others), we must always be careful and avoid leaping to the conclusion that this or that article describes the way things were done in fourteenth-century Serbia."