premise: With the Dutch concentrating once more on Java and the Moluccas in the 18th century, the Bugis took advantage of the vacuum by raiding Perak and Kedah, imposing their chieftains in Selangor and becoming the power behind the throne in Johor.
hypothesis: With the Dutch concentrating on Java, Bugis raided Perak and Kedah becoming the power behind the throne in Johor.