In 1780 Tidore was forced to sign a treaty that reduced it to a Dutch vassal. The discontented Prince Nuku left Tidore and declared himself Sultan of the Papuan Islands. This was the beginning of a guerilla war which lasted for many years. The Papuans, south-east Halmaherans and east Ceramese sided with the rebellious Prince Nuku. The British sponsored Nuku as part of their campaign against the Dutch in the Moluccas. Captain Thomas Forrest was intimately connected with Nuku and represented the British as ambassador. Nuku could finally take Tidore in 1797 and helped the British to conquer Ternate in 1801. However, his successor Zainal Abidin was expelled by Dutch forces in 1806 and Tidore was firmly brought under colonial rule.