Julius Wellhausen is known as the father of the Classical form of the source hypothesis. The purpose of this thesis is to examine Wellhausen‘s life, his greatest works and his influences on the study of the Pentateuch, including observing the process that paved the way for him to become the bearer of this title. Lastly, whether his source hypothesis has any relevance with the study of the Pentateuch in this day and age will also be answered. In the first chapter the role of Old Testament, critics like Spinoza, Simon, Astruc, De Wette, Hupfeld, Reuss, Kuenen and Graf will be examined. They all played a part in establishing the source hypothesis to which Wellhausen gave its final form. The era of the Enlightenment got momentum in the beginning of the nineteenth century. This movement also played a major role in creating the environment in which a critical examination of the Bible and its sources could be done. Wellhausen was influenced by this new way of thinking and was helped by the findings of other Old Testament critics that preceded him. In chapter two, his student life and the role of his teacher Heinrich Ewald will be examined. One of Wellhausen‘s aims was to write a history of Israel. To execute this he required sources. In chapter three, the first chapter (Genesis) of his book, Die Composition des Hexateuchs will be examined to get an idea of the method he used in the recognition, grouping and dating of the sources. The sources he identified in Genesis were the Yahwist, Elohist, Jehovist and Q (book of the four covenants and later called the Priestly source). Wellhausen used these sources to construct a history of Israel. In Chapter four an examination of his Geschichte Israels up to the beginning of the Christian era will be done. His greatest work was most certainly, his Prolegomena zur Geschichte Israels and in chapter five this masterpiece will be examined with special emphasis on the first part, namely Geschichte des Kultus. After Wellhausen has compared the different sources with each other, he came to certain conclusions. During the religion of Israel there was a development that can be traced from the earlier sources of the Yahwist(J), Elohist(E) to Deuteronomy(D) and finally to the Priestly Source(P). Early sources indicate that the worship of Israel was a spontaneous and free willing act. There were no rules regarding the place of worship, sacrifice, the sacred feasts and the clergy. In Deuteronomy this have now changed and laws were introduced regarding these aspects which the Israelites should adhere to. In the Priestly Source these laws are now assumed. From the outcome of these findings, it was clear for Wellhausen that the Priestly Source is the youngest of the sources. Therefore P should be dated in the exile or post-exilic period. Chapter six is a summary of Wellhausen‘s source hypothesis and how his source hypothesis assisted other scholars during their own research and findings. This study will close with a modern view on his source hypothesis and its relevance for today.