These documentary approaches were in competition with two other models, the fragmentary and the supplementary.[19] The fragmentary hypothesis argued that fragments of varying lengths, rather than continuous documents, lay behind the Torah; this approach accounted for the Torah's diversity but could not account for its structural consistency, particularly regarding chronology.[4] The supplementary hypothesis was better able to explain this unity: it maintained that the Torah was made up of a central core document, the Elohist, supplemented by fragments taken from many sources.[4] The supplementary approach was dominant by the early 1860s, but it was challenged by an important book published by Hermann Hupfeld in 1853, who argued that the Pentateuch was made up of four documentary sources, the Priestly, Yahwist, and Elohist intertwined in Genesis-Exodus-Leviticus-Numbers, and the stand-alone source of Deuteronomy.[20] At around the same period Karl Heinrich Graf argued that the Yahwist and Elohist were the earliest sources and the Priestly source the latest, while Wilhelm Vatke linked the four to an evolutionary framework, the Yahwist and Elohist to a time of primitive nature and fertility cults, the Deuteronomist to the ethical religion of the Hebrew prophets, and the Priestly source to a form of religion dominated by ritual, sacrifice and law.[21]