Similarly, Malaya lost much of its population as a result of the campaigns of Aceh in the period 1618-24. - Anthony Reid

The Malay population of the coastal low-lands of Malaya, Sumatra, and Borneo gradually absorbed animist hill peoples during the five centuries before 1900, by a mixture of raiding, tribute, and purchase, especially of children.

In densely settled wet-rice areas much of the loss of population was caused by destruction of food crops-either as a tactic of war or as a result of the passage of thousands of troops. In Sultan Agung's campaigns in 1620-25 against the coastal regions of East Java and Madura, eighty thousand troops besieged Surabaya and its nearby towns off and on for five years, devastating all the rice crops and even poisoning and damming up the river water of the city. The Dagh-Register recorded that after these campaigns "in Surabaya not more than 500 of its 50 to 60,000 people were left, the rest having died or gone away because of misery and famine" . Even on the side of Mataram there must have been enormously heavy losses, not only from the famine and disease that beset the unsuccessful besiegers of Batavia in 1628-29, but also from "the lack of men, so that they had not been able to bring the water to the rice fields" during the wars against Madura in 1624, with the result that the major rice-growing areas of Mataram itself were barren.

According to the Hikayat Banjar (432-37), the Islamization of Banjarmasin was effectively determined when opposing claimants to the throne decided on single combat to avoid a civil war.