When repeated Burmese invasions resulted in the destruction and defeat of the Siamese Ayutthaya Kingdom in 1767 by the Burmese Konbaung dynasty, neighbouring Malay tributary states began to assert their independence from Siam. To further develop Perak's tin mines, the Dutch administration suggested that its 17th Sultan, Alauddin Mansur Shah Iskandar Muda, should allow in Chinese miners. The sultan himself encouraged the scheme in 1776, requesting that additional Chinese workers be sent from Dutch Malacca. The Fourth Anglo-Dutch War in 1780 adversely affected the tin trade in Perak, and many Chinese miners left. In a move which angered the Siamese court, neighbouring Kedah's Sultan Abdullah Mukarram Shah then entered into an agreement with the English East India Company (EIC), ceding Penang Island to the British in 1786 in exchange for protection. </ref>