He seized the throne after killing his father, Abdul Ghafur Muhiuddin Shah and elder brother, the heir apparent Raja Abdullah.
[3][4] Dong-Xiyang kao ('A study of the Eastern and Western Oceans'), a 1618 Chinese account written during the Ming dynasty recorded that he had killed his father and elder brother Raja Abdullah, and took the throne for himself.
[5] The Chinese account further describes his short reign with the increase in pirate activities sanctioned by the Sultan himself with the association of Brunei.
[6] Alauddin is also said to have improved the port facility to facilitate trade, when he erected a number of shops and merchant quarters.
[10] Some of the words are unclear and indecipherable: Original Jawi text ..السلطان علاء الدين رعايتساه ابن عبد الغفار شاه // الواثق بال..القيام با..خلد الله ملكه وسلطانهTransliteration al Sultan Alauddin Riayat Shah ibn Abdul Ghafar Shah // al-wathiq bi-al..al-qaim bi..khallada Allah mulkahu wa-sultanahuTranslation The Sultan Alauddin Riayat Shah son of Abdul Ghafar Shah // he who trusts in the..he who is steadfast..may god preserve his realm and dominionThe seal is regarded as the earliest known Islamic seal from the Malay Peninsula.