Siak treaty in 1858

Jambi recognized Dutch sovereignty after a brief military intervention in 1834 and Indragiri in 1838, but under the London treaty Britain objected to Dutch expansion north of the Equator and the Dutch had no formal presence in Indragiri.

North of Indragiri, however, the sultanate of Siak experience internal political struggles in the 1850s and the Sultan appealed for Dutch protection. The Britain reluctantly permitted the Dutch to establish their hegemony in 1858 in order to preserve regional stability.

 In the Siak Treaty (1858) which was subsequently concluded the Sultan pledged his allegiance to the Netherlands Indies Government. In this treaty the Government at the same time undertook to maintain the rights of the Sultan in his dependencies.

Siak Treaty gave the Dutch sovereignty over Siak and which counted as the state’s territories as far north as Tamiang, the border state of Aceh. The article in the treaty defined the boundaries as far as Alas and Langkat and thus including pepper ports which were both under Aceh’s jurisdiction and important to British trade. The British objected and in 1863-5 sent gunboats to these pepper ports.
Siak treaty in 1858