Portugal and the Netherlands divide the island of Timor

Background. Prior to the 1859 treaty, Portugal and the Netherlands shared the island of Timor. The treaty was part of a series of agreements signed in 1851, 1854, and 1859 to define the border. Across this series, Portugal ceded its remaining territory and claims on Flores and the Solor islands, while the Netherlands ceded Maubara and Citrana to Portugal and dropped its claim on Atauro; the 1859 treaty itself specifically ceded Maubara and Ambeno and transferred Ataúro.

Treaty Terms. The Treaty of Demarcation and Exchange was signed on 20 April 1859. Portugal ceded Larantuca, Sicca, and Paga on Flores, Wouré on Adonara, and Pamung Kaju on Solor. In return, the Netherlands ceded the kingdoms of Maubara and Ambeno on Timor, as well as the island of Ataúro. The treaty also established boundaries between Portuguese and Dutch territories on Timor.

Financial Arrangements. As compensation, the Netherlands cancelled a debt of 80,000 florins borrowed by Portugal in 1851. Additionally, the Netherlands agreed to pay an extra 120,000 florins, to be delivered one month after the ratification of the treaty. This financial component was integral to the exchange of possessions in the archipelago.

Implementation. The 1859 border treaty was not implemented all at once, with local transfers out of sync with the official ratification in August 1860. The treaty's occurrence date is 20 April 1859; August 1860 marks its ratification, not its signing.