The title of "Pengiran" was mentioned in sixteenth century European records and was written on local tombs dating to the same period. The "Silsilah Raja-raja Brunei", which is the genealogy of Brunei rulers, shows that ranking within "Pengiran" had already existed since the reign of Sultan Muhammad Hassan, 1582-1598. Simultaneously, there also occurred other branches of the Brunei nobles from the ... [Show full abstract] reigns of other Sultans of Brunei. This paper-using the qualitative approach, historical method, and literature review-demonstrates that there was a restructuring to the ranking of Brunei nobles during the reign of Sultan Haji Omar Ali Saifuddien III, 1950-1967, specifically between 1958 and 1959. The restructuring, which occurred on the eve and following the promulgation of the 1959 Constitution, was indirectly influenced by the role of Sultan Hashim Jalilul Alam Aqamaddin, 1885-1906, in the 1905/1906 Supplementary Agreement. Sultan Hashim only wanted the descendants from him to be the future Sultans of Brunei which in turn, in 1959, distinguished nobles of Sultan Hashim descendants to nobles of non-Sultan Hashim's descendants. Another factor is the growing numbers of "Pengiran" from the nineteenth century. However, the "Pengiran Kebanyakan" proved to have no clear definition largely, because it was a product of the restructuring. This was also because the restructuring had tried to simplify the noble ranking, which was categorically wider and complex in the past.