Abdul Hakkul Mubin was once known as Pengiran (Prince) Abdul Mubin. However in 1660 his son was killed by the son of the reigning Sultan Muhammad Ali. In revenge he killed Muhammad Ali and took the throne, taking the name Abdul Hakkul Mubin. He tried to appease the previous Sultan's followers by appointing Muhammad Ali's grandson, Muhyiddin, as the new Bendahara ("Chief Minister"). However Muhammad Ali's supporters convinced Muhyiddin to take revenge sparking the Brunei Civil War. Abdul Hakkul Mubin's rule, and the Brunei Civil War, ended with his death and Muhyiddin's victory in 1673.
The earliest historical record of the Sultans of Brunei is not clearly known due to the poor early documentation of Brunei history. In addition there has been an effort to Islamise the history, with the "official history" not matching up with verifiable foreign sources  The Batu Tarsilah - the genealogical record of the kings of Brunei - was not started until 1807. Therefore, much of the intepretation on history relied on earlier Chinese sources and legends. It seems that the early Sultanate of Brunei was dependent on Chinese support, and perhaps early Sultans were of Chinese origin. Furthermore the earliest Sultans may have been practising the Hindu or Buddhist religions, with early names indicating this origin..