In the early 18th century, the descendants of the Sultan and the Regent of Johor where fighting for power. Bugis aristocrats from Celebes was asked to assist the Regent of Johor, and managed to achieve control of Riau due to the internal struggle between the members of the Johor Sultanate. The Bugis were great traders and made Bintan as a major trading center. Riau and Bintan also attracted British, Chinese, Dutch, Arabic and Indian traders. The Dutch however started to look upon Riau and the Bugis as a dangerous rival to Dutch trade in the region, drawing away trade from their ports in Malacca and Batavia (Jakarta). A Dutch fleet attacked Riau in 1784 but failed to hold the islands. Another attempt later the same year also failed before they managed to break the Bugis blockade of Malacca in June 1784. The Bugis commander, Raja Haji was killed during battle and the Bugis units retreated, which opened the way for a Dutch counterattack on Riau. The Bugis was expelled from Bintan and Riau, and a treaty between the Dutch and the Malay sultans granted Dutch control over the area. The treaty caused much anger among Malay rulers, and again in 1787 a force that was offered refuge by Sultan Mahmud drove out the Dutch. This also led to the return of the Bugis and the rivalry between Bugis and Malay. Peace between the two parties was finally reached in 1803. Around this time Sultan Mahmud gave Penyengat Island as a wedding gift to his bride, Raja Hamidah, Raja Ali Haji's daughter. Penyengat became for a period the center of government, Islamic religion and the Malay culture.