Following the Battle of Hastings in 1066 CE, Duke William II of Normandy, became the first Norman king of England. The Norman royal dynasty ruled for many years, but they had only three patrilineal kings, hence it was believed that the House of Normandy had died out in the male line. However, William was a direct male descendant of Duke Rollo of the Normans. Rollo together with the members of the House of Boulogne and the House of Montgomery are descended from the Great Norse family of Ulvungar. The members of the Ulvungar dynasty are directly descended from the ancient inhabitants of Mesopotamia in the Fertile Crescent. The methodology followed in this work was to obtain DNA samples from living direct male descendants from the members of the Ulvungar dynasty, with well-accepted documentation to confirm their human Y-Chromosome DNA haplogroup. In this study, the test results of DNA samples obtained from living direct male descendants of the House of Montgomery, in addition to other supporting DNA samples, are analysed to confirm the human Y-Chromosome DNA haplogroup of the Norman kings of England and their families. It was found that they are positive to the human Y-Chromosome DNA haplogroup J2 (subclade J2a-L26) which can be shown to have originated in the Fertile Crescent.