Task: Question Generation
Input (English): Passage: Despite the Portuguese proclaiming themselves as hostile to the Spanish crown, the VOC nevertheless took the opportunity to prise away the string of coastal fortresses that comprised the Portuguese Empire: Malacca finally succumbed in 1641. Important battles also took place in the South China sea, initially with combined fleets of Dutch and English vessels, and subsequently exclusively Dutch ships assaulting Macau. Dutch attempts to capture Macau, to force China to replace the Portuguese or to settle the Pescadores failed, in part because of the long-standing diplomacy between the Portuguese and the Ming, but the Dutch were ultimately successful in acquiring the monopoly of trade with Japan. while the Dutch were unable in four attempts to capture Macau from where Portugal monopolised the lucrative China-Japan trade. The Dutch established a colony at Tayouan in 1624, present-day Anping in the south of Taiwan, known to the Portuguese as Formosa and in 1642 the Dutch took northern Formosa from the Spanish by force. The Dutch intervened in the Sinhalese-Portuguese War on Ceylon from 1638 onwards, initially as allies of the Kingdom of Kandy against Portugal. The Dutch conquered Batticaloa in 1639 and Galle in 1640 before the alliance broke down. After a period of triangular warfare between the Dutch, Portuguese and Kandyans, the alliance was remade in 1649. After exploiting and then double-crossing their Kandyan allies, the Dutch were able to capture Colombo in 1656 and drove the last Portuguese from Ceylon in 1658. Sporadic warfare with Kandy continued for over a century.
Output (English): How many years after the remade alliance did the Dutch capture Colombo?