This 1859 treaty formally demarcated colonial borders between Portugal and the Netherlands in the Solor and Timor archipelago, shaping the territorial division that influenced modern Timor-Leste's boundaries.
Key Facts
- Date signed
- 20 April 1859
- Date ratified
- 18 August 1860
- Territories ceded by Portugal
- Larantuca, Sicca, Paga (Flores), Wouré (Adonara), Pamung Kaju (Solor)
- Territories ceded by Netherlands
- Maubara, Ambeno (Timor), and island of Ataúro
- Portuguese plenipotentiary
- António Maria de Fontes Pereira de Melo, Minister of Internal Affairs
- Dutch plenipotentiary
- Maurits Jan Heldewier, chargé d'affaires
Location
Cause → Event → Consequence
Portugal and the Netherlands both held overlapping and intermingled colonial possessions across the islands of Solor, Flores, Adonara, and Timor in the Indonesian Archipelago, creating administrative ambiguity and potential conflict that necessitated a formal territorial settlement between the two kingdoms.
On 20 April 1859, representatives of the Kingdom of Portugal and the Netherlands signed a treaty demarcating their respective colonial borders in the Solor and Timor archipelago. Portugal ceded several holdings on Flores, Adonara, and Solor, while the Netherlands transferred the kingdoms of Maubara and Ambeno on Timor and the island of Ataúro to Portugal.
The treaty was ratified on 18 August 1860 and established clearer sovereign boundaries between the two colonial powers in the region. The Portuguese-held territories on Timor consolidated into what would eventually become East Timor (Timor-Leste), while the ceded islands became part of the Dutch East Indies, later Indonesia.
Political Outcome
Portugal and the Netherlands exchanged colonial territories in the Solor and Timor archipelago, formally demarcating their respective borders in the region.
Intermingled Portuguese and Dutch colonial possessions across Flores, Adonara, Solor, and Timor with unclear boundaries
Consolidated Dutch control over Flores, Adonara, and Solor territories; consolidated Portuguese control over Maubara, Ambeno, and Ataúro on Timor